Toluene was refluxed over sodium and distilled at atmospheric pressure under nitrogen.

5. EXPERIMENTAL

5.1. M

Toluene was refluxed over sodium and distilled at atmospheric pressure under nitrogen.

Tetrahydrofurane was refluxed over Na/K alloy and distilled at atmospheric pressure under nitrogen.

Dichloromethane was refluxed over CaH

and distilled at atmospheric pressure under nitrogen.

Anisole and diethylene glycol dimethyl ether (diglyme) were kept at 100 °C over sodium for 4 hours and then distilled under reduced pressure.

Triethylamine was refluxed over KOH and distilled under nitrogen.

α,α’-Azobis(isobutyronitrile) (AIBN) was recrystallized from methanol.

Styrene was washed with 5% NaOH and water. After drying over Na

SO

, it was distilled under reduced pressure.

The 3,5-Di-t-butyl-4-hydroxytoluene (BHT) was purchased from Merck and used without further purifications.

1H,1H,2H,2H-perfluorodecyl acrylate and 1H,1H,2H,2H-perfluorododecyl alcohol were purchased from Fluorochem and used without further purifications.

4-Vinylbenzoic acid, 4-(dimethylamino)pyridine (DMAP, ≥ 99%), N,N’- dicyclohexylcarbodiimide (DCC, 99%), 2,2’-bipyridine (Bipy, ≥ 99%), copper(I) bromide (99.999%), copper(I) chloride (99.995%), N,N,N’,N’’,N’’-pentamethyldiethylenetriamine (PMDETA, 99%), α-bromoisobutyryl bromide (98%), methyl 2-bromoproprionate (MBrP, 98%), 1-phenylethyl bromide (1-(PE)Br, 98%) and 4-pyrrolidinopyridine (PPy, 99%) were purchased from Aldrich and used without further purifications.

The ethoxylated fluoroalkyl surfactant, Zonyl FSO-100 (registered trademark of E. I. du Pont de Numours & Co) was also obtained by Sigma-Aldrich.

Polydimethylsiloxane monocarbinol terminated (MCR-C12 (1000 g/mol), MCR-C18

(5000 g/mol) and MCR-C22 (10000 g/mol)), monomethacryloxypropryl terminated

polydimethylsiloxane (MCR-M11 (1000 g/mol)) and (3-glycidoxypropyl)-

trimethoxysilane (GPS) were purchased from Gelest and used without further

purifications.

178

Methyl 2-(bicyclo[3.1.0]hex-1-yl)acrylate [145] (BCL CH

) were kindly provided by Dr.

N. Moszner (Ivoclar-Vivadent, Schaan, Liechtenstein).

Polystyrene-b-poly(ethylene-co-buthylene)-b-polystyrene (SEBS) triblock thermoplastic elastomers (KRATON G1652M) and SEBS grafted with 1.4–2.0 wt % of maleic anhydride (MA-SEBS, KRATON FG1901X) were received from KRATON Polymers.

The styrene content of both SEBS and MA-SEBS was ∼ 30 wt %.

179

5.2. S

-

5.2.1. Synthesis of the poly(oxyethylene perfluoroalkyl) 4-vinylbenzoate (Sz)

COO(CH₂CH₂O)_xCH₂CH₂(CF₂CF₂)_yF

0.50 g (3.375 mmol) of 4-vinylbenzoic acid, 41 mg (0.337 mmol) of DMAP and 20 mL of anhydrous dichloromethane were added to a three necked round bottom flask under nitrogen atmosphere. The solution was cooled to 0°C and 0.695 g (3.368 mmol) of DCC in 20 mL of anhydrous dichloromethane was slowly added. The mixture was kept under stirring for 15 min at 0 °C and for 1 h at room temperature. Then, a solution of 2.329 g (3.37 mmol) of Zonyl FSO-100 in 10 mL of dichloromethane was slowly dropped into the flask. The reaction mixture was kept under stirring at room temperature for 62 h.

The white precipitate formed during the reaction was filtered off and the organic solution was washed with 5% Na

CO

(or NaHCO

), with 5% HCl and water and dried over NaSO

. The solvent was then evaporated under vacuum to give 2.528 g (yield 92%) of Sz as a yellow semi-solid compound.

1

H NMR (CDCl

): δ (ppm) = 2.5 (2H, CH

CF

), 3.2−4.2 (20H, CH

O), 4.5 (2H, COOCH

), 5.4 and 5.9 (2H, CH

=), 6.7 (1H, CH=), 7.5 and 8 (4H, aromatic).

FT-IR (film): ! (cm

) = 3090−3044 (ν C−H aromatic), 2874 (ν C−H aliphatic), 1716 (ν

C=O), 1608 (ν C=C aromatic), 1508 and 1455 (δ C−H aliphatic), 1400−1000 (ν C−O and

ν C−F), 653 (ω CF

).

180 5.2.2. Homopolymers and random copolymers 5.2.2.1. Homopolymers P(Sz)

COO(CH₂CH₂O)_xCH₂CH₂(CF₂CF₂)_yF

0.50 g (0.61 mmol) of Sz, 5 mg of AIBN, 2.5 mL of distilled diglyme and 1 mL of trifluorotoluene were introduced into a glass vial and degassed by several freeze–thaw pump cycles. The polymerization was carried out at 65 °C for 48 h. The polymer was purified by precipitations into n-hexane from tetrahydrofurane yielding to 0.345 g (69%

yield) of a viscous yellowish polymer.

Data relevant to all the polymerization experiments are reported in Table 5.1.

Table 5.1. Experimental conditions for the synthesis of P(Sz).

Run Sz

g (mmol)

Solvent mL/mL

AIBN mg (mmol)

time h

Yield

% P(Sz)1 0.500 (0.61) D/T (2.5/1) 5 (0.030) 48 69

P(Sz)2 2.800 (3.44) D (10) 28 (0.170) 72 72

P(Sz)3 2.524 (3.10) D (12) 26 (0.158) 8 26

a) D = diglyme, T = trifluorotoluene.

1

H NMR (CDCl

): δ (ppm) = 1.0−2.0 (3H, CH

CH), 2.4 (2H, CH

CF

), 3.0−4.2 (20H, CH

O), 4.4 (2H, COOCH

), 6.4 and 7.6 (4H, aromatic).

FT-IR (film): ! ^(cm

) = 3034 (ν C−H aromatic), 2878 (ν C−H aliphatic), 1722 (ν C=O),

1609 (ν C=C aromatic), 1509 and 1454 (δ C−H aliphatic), 1400−1000 (ν C−O and ν

C−F), 654 (ω CF

).

181 5.2.2.2. Random copolymers P(S-co-Sz)

COO(CH₂CH₂O)_xCH₂CH₂(CF₂CF₂)_yF

As an example, 2.134 g (2.62 mmol) of Sz, 0.8 g (7.692 mmol) of S and 10 mL of distilled diglyme were introduced into a glass vial in the presence of 31 mg of AIBN as a radical initiator. After four freeze-thaw pump cycles the vial was sealed under vacuum, and the polymerization was let to proceed for 8 h at 65 °C. The polymer was then precipitated into methanol and purified by repeated precipitations from tretrahydrofurane into methanol (21% yield).

Data relevant to all the polymerization experiments are reported in Table 5.2.

Table 5.2. Synthesis of the copolymers P(S-co-Sz).

Run Sz

g (mmol)

S g (mmol)

AIBN mg (mmol)

time h

Yield

% P(S-co-Sz)74 1.334 (1.64) 1.500 (14.423) 29 (0.177) 14 42.5 P(S-co-Sz)65 2.134 (2.62) 0.800 (7.692) 31 (0.189) 8 21 P(S-co-Sz)34

2.600 (3.19) 0.329 (3.163) 28 (0.170) 72 75

a) The polymer was purified by re-precipitations in n-hexane because of the high amount of Sz in the polymer chain.

As an example, for P(S-co-Sz)65:

1

H NMR (CDCl

): δ (ppm) = 1.0−2.2 (8.47H, CH

CH), 2.4 (2H, CH

CF

), 3.0−4.2 (20H, CH

O), 4.4 (2H, COOCH

), 6.1−8.1 (13.12H, aromatic).

FT-IR (film): ! (cm

) = 3080−3000 (ν C−H aromatic), 2922 (ν C−H aliphatic), 1722 (ν

C=O), 1608 (ν C=C aromatic), 1493 and 1454 (δ C−H aliphatic), 1400−1000 (ν C−O and

ν C−F), 759 and 699 (δ C−H aromatic), 654 (ω CF

).

182

5.2.3. Synthesis of polystyrene macroinitiators P(S)

Br

As an example, 5 mL (43.702 mmol) of S, 0.255 g (1.635 mmol) of Bipy, and 74 µL (0.542 mmol) of 1-(PE)Br were introduced into a dry Schlenk flask under nitrogen. The solution was purged with nitrogen for 15 min and then 78 mg (0.544 mmol) of CuBr was added to the glass tube. After four freeze-thaw pump cycles the polymerization was let to proceed under nitrogen for 330 min at 110 °C. When the reaction was stopped the polymer mixture was dissolved in THF and then was eluted on neutral alumina to remove the catalyst. The solvent was removed under vacuum and the polymer was purified by repeated precipitations from tretrahydrofurane into methanol (73% yield).

Data relevant to all the polymerization experiments are reported in Table 5.3.

Table 5.3. Synthesis of the macroinitiators P(S).

Run S

g (mmol)

1-(PE)Br mg (mmol)

CuBr mg (mmol)

Bipy g (mmol)

time min

Yield

% P(S)2.7 27.270 (262.211) 808 (4.367) 625 (4.357) 2.049 (13.119) 90 50 P(S)4.1 27.270 (262.211) 808 (4.367) 623 (4.347) 2.047 (13.035) 180 68 P(S)5.3 4.545 (43.702) 100 (0.542) 78 (0.544) 0.255 (1.635) 330 73 P(S)6.1 18.180 (174.81) 404 (2.183) 313 (2.182) 1.022 (6.548) 330 85 P(S)8.4 27.270 (262.211) 303 (1.641) 237 (1.652) 0.771 (4.936) 330 59

As an example, for P(S)5.3:

1

H NMR (CDCl

): δ (ppm) = 1.0−2.2 (3H, CH

CH), 6.1−7.4 (5H, aromatic).

FT-IR (film): ! ^(cm

) = 3050−3020 (ν C−H aromatic), 2930 (ν C−H aliphatic), 1601 (ν

C=C aromatic), 1493 and 1452 (δ C−H aliphatic), 756 and 698 (δ C−H aromatic).

183 5.2.4. Synthesis of block copolymers P(S-b-Sz)

Br m n

COO(CH₂CH₂O)_xCH₂CH₂(CF₂CF₂)_yF

As an example, 0.195 mg (0.04 mmol) of P(S)5.3 and 52 mg (0.333 mmol) of Bipy were introduced into a dry Schlenk flask, which was then evacuated and flushed with nitrogen three times. A solution of 0.60 g (0.74 mmol) of Sz in 3.5 mL of anisole was added to the glass tube under nitrogen. The mixture was purged with nitrogen for 30 min and then 18 mg (0.125 mmol) of CuBr was added. Finally, the glass vial was subjected to four freeze- thaw pump cycles. The polymerization was let to proceed for 24 h at 115 °C. When the reaction was stopped the polymer mixture was dissolved in THF and then eluted on neutral alumina to remove the catalyst. The solvent was removed under vacuum and the row polymer was purified by repeated precipitations from chloroform into methanol (39%

yield).

Data relevant to all the polymerization experiments are reported in Table 5.4.

As an example, for P(S5.3-b-Sz)75:

1

H NMR (CDCl

): δ (ppm) = 1.0−2.2 (12H, CH

CH), 2.4 (2H, CH

CF

), 3.0−4.2 (20H, CH

O), 4.4 (2H, COOCH

), 6.1−8.1 (19H, aromatic).

19

F NMR (CDCl

/CF

COOH): δ (ppm) = −6 (3F, CF

), −38 (2F, CF

CH

), −45 to −48 (10F, CF

), −51 (2F, CF

CF

).

FT-IR (film): ! (cm

) = 3080−3000 (ν C−H aromatic), 2922 (ν C−H aliphatic), 1722 (ν

C=O), 1608 (ν C=C aromatic), 1493 and 1454 (δ C−H aliphatic), 1400−1000 (ν C−O and

ν C−F), 759 and 699 (δ C−H aromatic), 654 (ω CF

).

184

Table 5.4. Synthesis of the amphiphilic block copolymers P(S-b-Sz).

Run Sz

g (mmol)

P(S) g (mmol)

CuBr mg (mmol)

Bipy g (mmol)

time h

Yield

% P(S8.4-b-Sz)95

1.724 (2.12) 3.500 (0.43) 60 (0.418) 195 (1.248) 66 86 P(S8.4-b-Sz)93

2.470 (3.03) 2.500 (0.30) 47 (0.328) 140 (0.896) 66 85 P(S8.4-b-Sz)88

3.379 (4.15) 1.700 (0.20) 30 (0.209) 95 (0.608) 66 75 P(S8.4-b-Sz)81

3.946 (4.85) 0.800 (0.09) 14 (0.097) 45 (0.288) 66 44 P(S8.4-b-Sz)68

4.923 (6.05) 0.500 (0.06) 9 (0.063) 28 (0.179) 66 31 P(S6.2-b-Sz)89 5.300 (6.51) 4.000 (0.64) 91 (0.634) 302 (1.933) 66 67 P(S5.3-b-Sz)90 1.000 (1.23) 0.640 (0.12) 87 (0.606) 264 (1.690) 64 45 P(S5.3-b-Sz)75 0.600 (0.74) 0.195 (0.04) 18 (0.125) 52 (0.333) 24 39 P(S5.3-b-Sz)72 4.666 (5.73) 1.500 (0.28) 142 (0.989) 466 (2.983) 66 71 P(S2.7-b-Sz)88 3.065 (3.76) 2.000 (0.74) 107 (0.746) 347 (2.222) 66 66 P(S2.7-b-Sz)87

3.063 (3.76) 2.000 (0.74) 106 (0.740) 348 (2.228) 24 66 P(S2.7-b-Sz)78

3.667 (4.50) 1.200 (0.44) 64 (0.446) 209 (1.338) 24 67 P(S2.7-b-Sz)67

3.400 (4.18) 0.559 (0.21) 31 (0.216) 97 (0.621) 66 51 P(S2.7-b-Sz)66

2.461 (3.02) 0.800 (0.30) 42 (0.293) 142 (0.909) 66 60 P(S2.7-b-Sz)58

4.878 (5.99) 0.165 (0.06) 8 (0.056) 28 (0.179) 66 20 P(S2.7-b-Sz)53

6.855 (8.42) 0.444 (0.16) 24 (0.167) 77 (0.493) 66 46

a) The raw copolymer was dissolved in chloroform and was purified by repeated extractions with distilled water until the disappearance of the green/blue color. Then it was purified by repeated precipitations from THF into methanol. ^b) The polymerization was carried out in diglyme.

185

5.3. S

5.3.1. Monomer synthesis

5.3.1.1. 2-(Bicyclo[3.1.0]hex-1-yl)acrylic acid (BCL COOH)

COOH

2.00 g (12.032 mmol) of methyl 2-(bicyclo[3.1.0]hex-1-yl)acrylate and 10 mg of BHT were dissolved in 30 mL of a degassed acetone/water solution (8:1 v/v). The solution was then cooled to 0 °C and 0.58 g (24.146 mmol) of LiOH in 6 mL of water was added dropwise under nitrogen. The mixture was stirred at room temperature for 5 days, then evaporated under vacuum, dissolved with water and washed with diethyl ether. The aqueous phase was cooled to 0 °C, washed with diethyl ether and then acidified with conc. HCl to pH = 1. Then the mixture was extracted with diethyl ether, dried over Na

SO

and evaporated under vacuum. 1.68 g (92% yield) of BCL COOH as a pale yellow crystalline solid was collected.

1

H NMR (CDCl

): δ (ppm) = 0.6 (2H, cyclopropane), 1.2 (1H, cyclopropane), 1.5−1.9 (6H, cyclopentane), 5.7 and 6.3 (2H, CH

=).

FT-IR (liquid film): ! (cm

) = 3100 (ν OH), 2937−2862 (ν C−H aliphatic), 1693 (ν C=O), 1426 (δ CH cyclic), 1359 (ν C−O ester), 1133 (ν C−F), 960−920 (γ CH vinyl).

5.3.1.2. 1H,1H,2H,2H-perfluorododecyl 2-(bicyclo[3.1.0]hex-1-yl)acrylate (BCL F10)

COO(CH₂)₂(CF₂)₁₀F

A solution of 1.60 g (10.513 mmol) of BCL COOH, 5.93 (10.512 mmol) of

1H,1H,2H,2H-perfluorododecyl alcohol and 0.31 g (2.092 mmol) of PPy in 40 mL of

anhydrous dichloromethane was cooled to 0 °C under nitrogen atmosphere and 2.17 g

186

(10.517 mmol) of DCC dissolved in 20 mL of anhydrous dichloromethane was slowly added. The mixture was kept under stirring at room temperature for 24 h. The precipitate formed during the reaction was filtered off and the organic solution was washed with 5%

HCl, 5% Na

CO

, and water and dried over NaSO

. The solvent was then evaporated under vacuum and the crude product was purified by silica gel column flash chromatography (230−400 mesh), using chloroform as eluent (Rf = 0.80) to give 4.67 g (62% yield) of BCL F10 as a pale yellow liquid.

1

H NMR (CDCl

): δ (ppm) = 0.6 (2H, cyclopropane), 1.2 (1H, cyclopropane), 1.5−1.9 (6H, cyclopentane), 2.5 (2H, CH

CF

), 4.4 (2H, COOCH

) 5.6 and 6.2 (2H, CH

).

13

C NMR (CDCl

/C

F

): δ (ppm) = 13−33 (C cycle), 57 (COOCH

), 107−123 (CF

), 126 (C=COO), 143 (CH

=), 166 (COO).

FT-IR (liquid film): ! (cm

) = 2962−2866 (ν C−H aliphatic), 1727 (ν C=O), 1624 (ν C=C), 1367 (ν C−O ester), 1117 (ν C−F), 954 (γ CH vinyl).

5.3.2. Polymer synthesis

5.3.2.1. Synthesis of P(BCL F10) homopolymer

COO(CH₂)₂(CF₂)₁₀F

5.3.2.1.1. Synthesis by conventional free radical polymerization

As an example, 1.50 g (2.149 mmol) of BCL F10, 11 mg of AIBN and 5 mL of trifluorotoluene were introduced into a glass vial and degassed by several freeze–thaw pamp cycles. After sealing under vacuum, the polymerization was carried out at 65 °C for 48 h. The polymer was purified by precipitations into methanol from trifluorotoluene leading to 1.27 g (98% yield) of P(BCL F10) as a white powder.

Data relevant to all the polymerization experiments are reported in Table 5.5.

187 Table 5.5. Synthesis of P(BCL F10) samples.

Run BCL F10

g (mmol)

Initiator mg

time h

Yield

%

P(BCL F10)a 1.50 (2.149) AIBN (11) 48 98

P(BCL F10)b

0.75 (1.074) AIBN (5) 72 93

P(BCL F10)c 0.75 (1.074) BPO (8) 72 98

P(BCL F10)d 0.75 (1.074) TBPO (9) 48 63

a) The polymerization was carried out in bulk.

5.3.2.1.2. Synthesis via ATRP

1 g (1.432 mmol) of BCL F10, 13 µL (0.063 mmol) of PMDETA, 2 mL trifluorotoluene and 7 µL (0.063 mmol) of methyl 2-bromopropionate (MBrP) were introduced into a dry Schlenk flask. After flushing nitrogen for 30 min, 9 mg (0.063 mmol) of CuBr was added under nitrogen and the solution was deoxygenated by four freeze-thaw pump cycles. The polymerization was let to proceed for 22 h at 110 °C. The polymer was purified by repeated precipitations into methanol from chloroform/trifluorotoluene (1:2 v/v) solution (15% yield).

1

H NMR (CDCl

): δ (ppm) = 0.9−2.0 (9H, CH, CH

in cycle), 2.0−3.1 (4H, CH

, CH

CF

), 4.4 (2H, COOCH

).

13

C NMR (CDCl

): δ (ppm) = 27−40 (C cycle), 56 (COOCH

), 107−123 (CF

), 124 (=CCOO), 148 (CH

= in cycle), 170 (COO).

FT-IR (film): ! (cm

) = 2962−2866 (ν C−H aliphatic), 1727 (ν C=O), 1624 (ν C=C), 1367 (ν C−O ester, ν C−F), 660 (ω CF

).

5.3.2.2. Synthesis of P(SiMA) hompolymer via ATRP

O(CH₂)₃ (SiO) SiC₄H₉ O

Br

10

As an example, 2.00 g (2.00 mmol) of monomethacryloxypropyl terminated

polydimethylsiloxane (SiMA), 42 µL (0.202 mmol) of PMDETA and 22 µL (0.198

188

mmol) of methyl 2-bromopropionate (MBrP) were introduced into a dry Schlenk flask.

After flushing nitrogen for 30 min., 29 mg (0.202 mmol) of CuBr was added under nitrogen and the solution was deoxygenated by four freeze-thaw pump cycles. The polymerization was let to proceed for 39 h at 100 °C. When the reaction was stopped the polymer mixture was dissolved in chloroform, precipitated in methanol and kept under stirring for the night. The polymer was further purified by extraction in methanol (64.4%

yield).

1

H NMR (CDCl

): δ (ppm): 0.15 (66H, SiCH

), 0.5 (4H, SiCH

), 0.7−2.3 (14H, SiCH

CH

CH

CH

, CH

CCH

, COOCH

CH

CH

Si), 3.9 (2H, COOCH

(CH

)

Si).

FT-IR (film): ! (cm

) = 2964 (ν CH aliphatic), 1736 (ν C=O, ester), 1263 (ν Si−CH

), 1200−1033 (ν C−O ester, ν Si−O), 800 (Si−CH

).

5.3.2.3. Synthesis of random copolymers P(BCL F10-co-SiMA)

O(CH₂)₃ (SiO) SiC₄H₉

10

O COO(CH₂)₂(CF₂)₁₀F

As an example, 0.149 g (0.213 mmol) of BCL F10, 0.851 g (0.85 mmol) of SiMA, 10 mg of AIBN and 5 mL of trifluorotoluene were introduced into a Pyrex glass vial. After three freeze-thaw pump cycles the vial was sealed under vacuum, and the polymerization was let to proceed for 67 h at 65 °C. The reaction mixture was diluted with 8 mL of a solution of chloroform/trifluorotoluene (1:1 v/v) and precipitated into methanol. The polymer was purified by repeated precipitations from solutions of trifluorotoluene/chloroform (1:1 v/v) into methanol at 0 °C to give P(BCL-co-SiMA)a (56% yield).

Data relevant to the other polymerization experiments are reported in Table 5.6.

189

Table 5.6. Synthesis of the copolymers P(BCL F10-co-SiMA).

Run BCLF10

g (mmol)

SiMA g (mmol)

AIBN mg (mmol)

time min

Yield

% P(BCL F10-co-

SiMA)a

0.149 (0.213) 0.851 (0.85) 10 (0.061) 67 56

P(BCL F10-co- SiMA)b

0.318 (0.455) 0.683 (0.68) 10 (0.061) 67 75

P(BCL F10-co- SiMA)c

0.512 (0.733) 0.488 (0.49) 10 (0.061) 67 75

P(BCL F10-co- SiMA)d

0.737 (1.056) 0.264 (0.26) 10 (0.061) 67 87

a) The polymer was purified by precipitations into methanol from 1:2 (v/v) chloroform/trifluorotoluene solution.

As an example, for P(BCL F10-co-SiMA)a:

1

H NMR (CDCl

): δ (ppm): 0.1 (272.10H, SiCH

), 0.5 (16.49H, SiCH

), 0.9−3.0 (70.20H, SiCH

CH

CH

CH

, CH

CCH

, COOCH

CH

CH

Si, CH

e CH cycle, =CCH

, CH

CF

), 3.9 (8.25H, COOCH

(CH

)

Si), 4.4 (2H, COOCH

CH

CF

).

19

F NMR (CDCl

/CF

COOH): δ (ppm): −6 (3F, CF

), −38 (2F, CH

CF

), −47 to −49 (14 F, CF

), −51 (2F, CF

CF

).

FT-IR (film): ! (cm

) = 2966 (ν C−H aliphatic), 1732 (ν C=O ester), 1642 (ν C=C),

1263 (ν Si−CH

), 1211−1150 (ν C−O ester, ν C−F), 1088−1028 (ν Si−O), 800 (Si−CH

),

659 (ω CF

).

190

5.4. S

-

5.4.1. Synthesis of bromine terminated polydimethylsiloxane macroinitiators

SiO SiCH₂CH₂CH₂OCH₂CH₂O C₄H₉SiO

n

O Br

As an example, 5.00 g (5.00 mmol) of polydimethylsiloxane monocarbinol terminated (PDMS-OH, = 1000 g/mol) was dissolved in 85 mL of anhydrous tetrahydrofurane. 1.74 mL (12.481 mmol) of triethylamine (Et

N) was added under nitrogen to the stirred solution. 0.77 mL (6.136 mmol) of α-bromoisobutyryl bromide in 15 mL of anhydrous tetrahydrofurane was slowly dropped. The reaction was carried out at ambient temperature for 24 h.

The solution was filtered to remove the bromide salt, and the solvent was removed under vacuum. The resulting yellow oil was taken up in dichloromethane and washed with saturated NaHCO

solution, 2.5% HCl, and distilled water. The organic layer was isolated and dried over sodium sulphate, filtered, and the volatiles were removed in vacuo to yield the product as a pale yellow oil (95% yield ).

Data relevant to all the experiment are reported in Table 5.7.

Table 5.7. Synthesis of bromine-terminated PDMS macroinitiators.

MI PDMS-OH (Mn)

g (mmol)

Et

N g (mmol)

BrBu

COBr mg (mmol)

Yield

% P(Si1.15) 1000

5.00 (5.00) 1.263 (12.481) 1.409 (6.136) 95 P(Si5)

5000

5.00 (1.00) 0.337 (3.330) 0.382 (1.662) 89 P(Si10)

10000

5.00 (0.50) 0.180 (1.779) 0.192 (0.835) 76

a) The polymer was subjected to a further purification process by extraction in methanol for two days. ^b) The polymer was subjected to a further purification process by precipitation from chloroform solution into methanol.

191 As an example, for P(Si1.15):

1

H NMR (CDCl

): δ (ppm) = 0.1 (72H, SiCH

), 0.6 (4H, SiCH

), 0.9 (3H, CH

CH

), 1.3 (4H, SiCH

CH

), 1.6 (2H, CH

CH

), 1.9 (6H, CCH

), 3.5 (2H, COOCH

CH

OCH

), 3.7 (2H, COOCH

CH

O), 4.4 (2H, COOCH

).

FT-IR (film): ! (cm

) = 2962 (ν C−H aliphatic), 1741 (ν C=O ester), 1263 (ν Si−CH

), 1164−1000 (ν C−O, ν Si−O), 801 (Si−CH

).

5.4.2. Synthesis of P(AF8) homopolymer via ATRP

Br

O OCH₂CH₂(CF₂CF₂)₄F

As an example, 2.394 g (4.620 mmol) of 1H,1H,2H,2H-perfluorodecyl acrylate (AF8), 64 µL (0.306 mmol) of PMDETA, 2 mL trifluorotoluene and 51 µL (0.305 mmol) of methyl 2-bromopropionate were introduced into a dry Schlenk flask, which was then evacuated and flushed with nitrogen three times. Then 44 mg (0.307 mmol) of CuBr was added under nitrogen and the solution was deoxygenated by four freeze-thaw pump cycles. The polymerization was let to proceed for 17 h at 114 °C. When the reaction was stopped the polymer mixture was dissolved in hexafluorobenzene, precipitated into methanol and kept under stirring for the night. The polymer was further purified by repeated precipitations into methanol from hexafluorobenzene solution (83% yield).

Data relevant to all the polymerization experiments are reported in Table 5.8.

As an example, for P(AF8)5:

1

H NMR (CDCl

/C

F

): δ (ppm) = 1.1−3.0 (5H, CHCH

, CHCH

, CH

CF

), 4.5 (2H, COOCH

CH

CF

).

FT-IR (film): ! (cm

) = 2967 (ν C−H aliphatic), 1738 (ν C=O ester), 1463 (δ C−H),

1202−1147 (ν C−O ester, ν C−F), 653 (ω CF

).

192

Table 5.8. Experimental conditions for the synthesis of P(AF8).

Run AF8

g (mmol)

MBrP mg (mmol)

CuX mg (mmol)

PMDETA mg (mmol)

time h

Yield

% P(AF8)1 1.500 (2.895) 12 (0.072) CuBr

11 (0.077) 13 (0.075) 24 61 P(AF8)2 1.500 (2.895) 24 (0.144) CuCl

10 (10.102) 17 (0.981) 48 76 P(AF8)3

1.968 (3.798) 21 (0.126) CuBr

18 (0.125) 22 (0.127) 24 35 P(AF8)4

3.607 (6.961) 46 (0.275) CuBr

40 (0.279) 48 (0.277) 17 91 P(AF8)5 2.394 (4.620) 51 (0.305) CuBr

44 (0.307) 53 (0.306) 17 83

a) The polymerization was carried out in bulk.

5.4.3. Synthesis of block copolymers P(Si-b-AF8)

SiO SiCH₂CH₂CH₂OCH₂CH₂O C₄H₉SiO

n

O

Br

O OCH₂CH₂(CF₂CF₂)₄F m

As an example, 2.00 g (0.20 mmol) of P(Si10), 1.037 g (2.0 mmol) of AF8, 39 µL (0.185 mmol) of PMDETA and 6.5 mL of trifluorotoluene were introduced into a dry Schlenk flask. After three freeze-thaw pump cycles, 27 mg (0.188 mmol) of CuBr was added under nitrogen and the solution was deoxygenated by four freeze-thaw pump cycles. The polymerization was let to proceed for 66 h at 115 °C. When the reaction was stopped the polymer mixture was dissolved in hexafluorobenzene (or a mixture of hexafluorobenzene and trifluorotuluene) and was extracted with distilled water, until the disappearance of the green/blue color. The solvent was removed under vacuum and the polymer was precipitated from hexafluorobenzene solution into methanol and kept under stirring for at least one day (69% yield).

Data relevant to all the polymerization experiments are reported in Table 5.9.

193

Table 5.9. Synthesis of block copolymers P(Si-b-AF8).

Run AF8

g (mmol)

P(Si) g (mmol)

CuBr mg (mmol)

PMDETA mg (mmol)

Yield

% P(Si10-b-AF8)94 1.037 (2.001) 2.000(0.20) 27 (0.188) 32 (0.185) 62 P(Si10-b-AF8)91 1.037 (2.001) 1.000 (0.10) 15 (0.104) 18 (0.104) 70 P(Si10-b-AF8)81

2.554 (4.929) 1.000 (0.10) 14 (0.097) 17 (0.098) 48 P(Si5-b-AF8)88

1.564 (3.018) 1.510 (0.30) 45 (0.314) 54 (0.312) 48 P(Si5-b-AF8)82

2.075 (4.001) 1.018 (0.20) 31 (0.216) 37 (0.213) 57 P(Si1.15-b-AF8)48 3.000 (5.790) 0.660 (0.58) 84 (0.586) 99 (0.571) 68 P(Si1.15-b-AF8)36 4.000 (7.719) 0.440 (0.38) 55 (0.383) 66 (0.381) 67

a) The copolymer was purified by repeated extractions in chloroform in order to remove the perfluorinated homopolymer eventually formed during the reaction.

As an example, for P(S10-b-AF8)94:

1

H NMR (CDCl

): δ (ppm) = 0.0 (95H, SiCH

), 0.6 (0.48H, SiCH

), 0.9−2.8 (6.68H, CH

CH

CH

CH

Si, SiCH

CH

CH

O, C(CH

)

, CHCH

, CH

CF

), 3.2−3.6 (0.48H, SiCH

CH

CH

OCH

), 4−4.6 (2.24H, CCOOCH

, COOCH

CH

CF

).

19

F NMR (CDCl

/CF

COOH): δ (ppm) = −6 (3F, CF

), −38 (2F, CF

CH

), −45 to −48 (10F, CF

), −51 (2F, CF

CF

).

FT-IR (film): ! (cm

) = 2963 (ν C−H aliphatic), 1738 (ν C=O, ester), 1260 (ν Si−CH

), 1149−1000 (ν C−O, ν C−F, ν Si−O), 800 (Si−CH

), 660 (ω CF

).

5.4.4. Synthesis of block copolymers P(Si-b-Sz)

SiO SiCH₂CH₂CH₂OCH₂CH₂O C₄H₉SiO

n

O

Br

COO(CH₂CH₂O)_xCH₂CH₂(CF₂CF₂)_yF m

As an example, 0.905 g (0.18 mmol) of P(Si5), 85 mg (0.544) of Bipy and a solution of

1.562 g (1.92 mmol) of Sz in 13 mL of distilled diglyme were introduced into a dry

Schlenk flask. The mixture was evacuated and flushed with nitrogen three times, and then

194

25 mg (0.174 mmol) of CuBr was added under nitrogen. After four freeze-thaw pump cycles, the polymerization was let to proceed for 66 h at 115 °C. When the reaction was stopped the polymerization mixture was precipitated into a solution of methanol/water 7:3 (v/v) and kept under stirring for days. Finally, the polymer was extracted with methanol for one day at room temperature (83% yield).

Data relevant to all the polymerization experiments are reported in Table 5.10.

Table 5.10. Synthesis of block copolymers P(Si-b-Sz).

Run Sz

g (mmol)

P(Si) g (mmol)

CuBr mg (mmol)

Bipy mg (mmol)

Yield

% P(Si10-b-Sz)96 1.660 (2.04) 1.000 (0.10) 14 (0.097) 47 (0.301) 46 P(Si10-b-Sz)94 1.540 (1.89) 0.550 (0.06) 16 (0.111) 52 (0.333) 40 P(Si5-b-Sz)86 1.562 (1.92) 0.905 (0.18) 25 (0.174) 85 (0.544) 83 P(Si5-b-Sz)79 1.553 (1.91) 0.477 (0.09) 13 (0.091) 42 (0.269) 60

As an example, for P(Si5-b-Sz)86:

1

H NMR (CDCl

): δ (ppm) = 0.0 (37.20 H, SiCH

), 0.6 (0.36H, SiCH

), 0.8−2.6 (6.26H, CH

CH

CH

CH

Si, SiCH

CH

CH

O, C(CH

)

, CHCH

, CH

CF

), 3.0−4.0 (20.36H, SiCH

CH

CH

OCH

, CH

O), 4.4 (2.18H, CCOOCH

, PhCOOCH

), 6.5 and 7.5 (4H, C=C aromatic).

FT-IR (film): ! (cm

) = 2962−2905 (ν C−H aliphatic), 1722 (ν C=O, ester), 1608 (ν

C=C aromatic), 1454 ( δ C−H aliphatic), 1400−1000 (ν Si−CH

, ν C−O, ν C−F, ν Si−O),

799 (Si−CH

), 707 (δ C−H aromatic), 660 (ω CF

).

195

5.5. P

SEBS-

The coatings for the biological testing were prepared by the bilayer strategy, as follows.

The glass slides were cleaned in hot piranha (concentrated sulphuric acid + 30 wt % hydrogen peroxide solution, 7:3 v/v), rinsed with distilled water, acetone and dried in the oven at 100 °C for about 10 min.

A 2% (w/v) solution of (3-glycidoxypropyl)-trimethoxysilane in 95% ethanol (pH adjusted between 4.5 and 5 using acetic acid) was prepared by adding the silane to the ethanol solution and stirring for 5 min. The slides were then soaked in this solution overnight, rinsed with ethanol, and heated in an oven at 110 °C for 20 min.

The GPS fuctionalized glass slides were coated by casting on a 12% (w/v) toluene solution of MA-SEBS and SEBS (56/44 w/w). They were allowed to dry in a closed chamber for two-three days until the solvent was evaporated.

After slides were annealed in an oven overnight at 120 °C, a 1.5% (w/v) toluene (or THF for the homopolymer P(Sz)) solution of either the fluorinated polymer alone or a blend of the fluorinated copolymer and SEBS was spray coated on the bottom layer using a Badger model 250 airbrush (50 psi air pressure) to obtain a polymer surface density of 1−1.5 mg/cm

. The surfaces were vacuum dried in an oven at 60 °C for 8 h and then annealed overnight at 120 °C.

According to the same procedure, two internal controls SEBS1 and SEBS2 were

prepared, in order to compare their antifouling and fouling-release properties with those

of the fluorinated surfaces. The formulations of all the coatings submitted to biological

assays are reported in Table 5.11.

196

Table 5.11. Composition of coatings submitted to biological testing.

Coating Layer SEBS-MA/SEBS

(w/w)

Polymer

bottom 56/44 -

Unipi9

top - P(S5.3-b-Sz)72/SEBS

90/10 (w/w)

bottom 56/44 -

UniPi17

top - P(S5.3-b-Sz)72

bottom 56/44 -

UniPi18

top P(Sz)

bottom 56/44 -

UniPi21

top - P(S2.7-b-Sz)53

bottom 56/44 -

UniPi22

top - P(S2.7-b-Sz)53/SEBS

90/10 (w/w)

bottom 56/44 -

UniPi23

top P(S2.7-b-Sz)53/SEBS

70/30 (w/w)

bottom 56/44 -

UniPi26

top - P(S8.4-b-Sz)81/SEBS

90/10

bottom 56/44 -

UniPi27

top - P(S8.4-b-Sz)81/SEBS

70/30 (w/w)

bottom 56/44 -

UniPi28

top - P(S8.4-b-Sz)81

bottom 56/44 -

SEBS1

top - SEBS

bottom 56/44 -

SEBS2

top - -

a) After deposition of the bottom layer and solvent evaporation the coatings were annealed at 120 °C for two nights.

197 5.6. B

5.6.1. Consortium of marine bacteria

Slides were pre-leached in a tank of deionized water for 7 days and conditioned in artificial seawater (ASW) for 1 h before the assay was started. A mixture of three different species of bacteria (Vibrio alginolyticus, Cobetia marina and Marinobacter hydrocarbonoclasticus) were used for the testing, after being repeatedly washed and centrifuged to remove excess extracellular polymeric substance (EPS) for optimal adhesion.

Slides were pre-leached in a tank of reverse osmosis water for 7 days and conditioned in ASW for 1 h before the assay started. Slides were immersed for 1 h in quadriperm plates containing 8 mL of suspension of the 3 bacteria mix with an optical density at 595 of 0.2 nm. Then they were rinsed with seawater to remove non-adhered cells and transferred to 8 mL of growth medium. After 4 h incubation and drying, 3 spots on each slide were subsequently stained with the fluorochrome Syto 13, followed by biomass quantification in a Tecan plate reader.

In order to evaluate fouling release properties, slides were treated as above, but after the growth step slides of each coating were rotated on the rotor (Fig. 5.1) for 10 min at 12 knots in natural seawater. The remaining biofilm was then quantified as described above.

The percentage removal was calculated using the following formula:

% removal = (biomass/biomass before release) ⋅ 100

Biofilm formation and release were normalized against the negative standard Epikote and

the positive standard T2 silastic, respectively.

198

(a) (b)

Figure 5.1. TNO rotor for hydrodynamic testing (a), rack for 5 standard microscope slides (b).

5.6.2. Pseudomonas fluorescens bacteria

Test samples were leached in circulating deionised water for 7 days. They were immersed in a glass tank containing 500 mL suspension of Pseudomonas fluorescens with a concentration of 10

cells/mL. The tank was transferred to a shaker-incubator at a low speed (20 rpm) at 28 °C for 1 h. The samples were removed and rinsed in sterile distilled water under controlled hydrodynamic conditions. A sample was moved down-up 20 times vertically in a glass tank (A) of sterile distilled water at 28 °C at a constant speed to remove adhered bacteria. It was then transferred to a second glass tank (B) containing sterile distilled water at 28 °C and sonicated in an ultrasonic bath to remove all the remaining attached bacteria. The number of bacteria in the tank A, D

(bacteria removed from the test sample) and the number of bacteria in the tank B, R

(bacteria remaining on the test sample) were determined after 24 h incubation on plate count agar medium at 28

°C, respectively, using a standard plating method for viable counts. The total number of bacteria, as colony-forming units (CFU) attached to the sample A

was the sum of the D

and R

. The average values of attached bacteria and percentage removal were calculated using the following formula:

A

= D

+ R

% removal = (D

/A

) ⋅ 100

199

Attachment and removal of bacterial were normalized against the negative Epikote standard and the positive T2 Silastic, respectively.

5.6.3. Ulva sporeling growth

Spores were released from plants collected from the seashore. The concentration of spores was adjusted to a standard concentration, typically 1 x 10

spores/mL, and 10 mL was added to each slide placed in a compartment of a plastic quadriperm dish. After a standard settlement period, typically 1 h in darkness, the slides were washed to remove unsettled spores. The slides were replaced in the dishes and growth medium added. The dishes were incubated in an illuminated incubator for 6−7 days, the medium being refreshed every 2 days. After 6−7 days, the slides had a green covering of sporelings (young plants). The motility of unsettled spores at the end of the settlement period was assessed qualitatively by observing their negative phototaxis.

The biomass on the slides was quantified before and after the exposure to flow channel, by measurement of the chlorophyll fluorescence. The percentage removal was calculated using the following formula:

% removal = (biomass after flow channel/biomass before flow channel ) ⋅ 100

The pecentage removal was normalized against that of the positive standard T2 Silastic.

A fluorescent multi-well plate reader (Genios Plus-Tecan) was adapted for the measurement of the chlorophyll fluorescence. The Tecan emits light of wavelength 430 nm, exciting the chlorophyll contained within the chloroplasts of the algal cells growing on the slide surface and then measures the 630 nm light, which was emitted as the pigment returns to ‘resting state’. The Tecan obtained multiple readings (240 per slide) working in a raster pattern across the slide. Data are expressed as RFU (Relative Fluorescence Units).

5.6.4. Diatoms

The assay procedure was similar to that described for Ulva sporelings. A culture of 4-old

day diatom cells was adjusted to a standard cell concentration after filtering to remove

200

any clumps of cells. The exact concentration of diatom was determined by extraction of chlorophyll with DMSO. 5 mL of the solution were filtered on a 0.45 µm nitrocellulose membrane and the filtered diatoms were immersed in DMSO for a hour. After extraction, the absorbance of chlorophyll a was read at 664 and 630 nm.

The concentration of chlorophyll was calculated using the following equation:

Reading @ 630 ⋅ 0.4 – Reading @ 664 ⋅ 11.47 = µg chlorophyll

/mL

10 mL of diatom solution were added to each slide placed in a compartment of a plastic quadriperm dish. After a standard settlement period, typically 2 h, in the light, the slides were washed to remove unattached cells. Diatoms settled on the surface by gravity so no surface selection processes were involved. The strength of attachment of the diatom cells was measured using the flow channel. Percentage removal was calculated with the previous formula and normalized against that of the positive standard T2.

5.6.4.1. Flow Channel

The water channel apparatus (Fig. 5.2) described in [167] was modified by fitting a

higher capacity pump. The flow channel held 6 microscope slides. A variable height

bedding system allowed each slide to be adjusted so that the surface was flush with the

surrounding channel wall. Turbulent flow was created in a 60 cm long low aspect ratio

section of channel preceding the slides. Exposure of slides to flow was standardized at 5

min. Flows of seawater (Instant Ocean) up to 4.9 m/s generated wall shear stresses up to

56 Pa. The fully-developed channel flow allowed accurate wall shear stress determination

from measurements of flow rate. Wall shear stresses were determined from streamwise

pressure drop measurements using the Reynolds-averaged Navier-Stokes equation [167].

201 Figure 5.2. Flow channel apparatus.

5.6.5. Barnacle cypris larvae

Batches of cypris larvae were cultured from batch cultures of adult Balanus amphitrite, originally collected by Dr D. Rittschof from pier pilings at Duke University Marine Laboratory, Beaufort, North Carolina USA and/or Dr K. Matsumura from Lake Hamana, Shizuoka, Japan. Adults were maintained in seawater at 23 °C with a 16 h: 8 h, light: dark cycle, constant aeration and were fed with freshly hatched 90% grade Great Salt Lake Artemia (brine shrimp) (Artemia International LLC). To obtain larval releases, adults were air-dried overnight before being placed in clean seawater, with no aeration, in the dark. The released nauplii were attracted to a cold light source, collected by pipette, and grown to the cypris stage in ASW at 28 °C with a 12 h: 12 h, light: dark cycle. Nauplii were fed Skeletonema costatum (diatom) grown in F/2 medium.

Development to the cyprid stage took between 4 and 5 days. The cyprids were collected using 250 µm plankton net and stored at 6 °C prior to use.

Cyprids were used after 3 days storage at 6°C. For the settlement assay, 10 cyprids were added to each slide in one large drop of artificial seawater (~ 1 mL) placed on the surface.

The slides were incubated for 24 h at 28 °C in the dark. The numbers of cyprids attached and/or metamorphosed were then enumerated and expressed as percentage settlement.

Polystyrene control slides were used to ensure the health and viability of the batch was within an acceptable range and to account for any variation between batches of cyprids.

Results were given as a mean percent increase or decrease in settlement compared to the

glass standard with 95% confidence intervals.

202 5.7. C

5.7.1. FT-IR Spectroscopy

Infrared spectra were recorded with a Spectrum One Perkin-Elmer Fourier Transform infrared spectrophotometer with 4 cm

resolution using 16 scans. Samples were pressed in a KBr pellet or cast on a KBr crystal plate.

5.7.2. NMR Spectroscopy

1

H and

C spectra were recorded on a Varian Gemini VRX 200, while

F spectra were obtained on a Varian Gemini VRX 300.

5.7.3. Size Exclusion Chromatography (SEC)

SEC was carried out with a Jasco PU-1580 liquid chromatograph equipped with two PL gel 5 µm Mixed-D columns, a Jasco 830-RI refractive index detector and a Perkin-Elmer LC75 UV detector. Polystyrene standards were used for calibration.

5.7.4. Differential Scanning Calorimetry (DSC)

Differential scanning calorimetry measurements were performed on a Mettler DSC 30 instrument. Samples of 5−20 mg were used with 10 °C/min or 20 °C/min heating and cooling rates. Nitrogen was used as purge gas at the flow rate of 30 mL/min. Temperature and energy calibrations were carried out using standard samples of tin, indium and zinc.

The phase transition temperatures of the polymers were taken as corresponding to the

maximum temperature in the relevant enthalpic peak. The glass transition temperature

was taken at the half devitrification of the polymer.

203 5.7.5. Thermal Gravimetric Analysis (TGA)

A TA Thermogravimetric Analyzer TGA Q500 was employed for TGA analysis.

Evaluations were performed on 4−20 mg samples at 10 °C/min under a 60 mL/min nitrogen flow from 30 °C to 700 °C.

5.7.6. Wide Angle X-Ray Diffraction (WAXD)

Wide angle X-ray diffraction patterns were obtained in collaboration with Dr. Bernard Gallot at the CNRS-LMOPS, Vernaison (France), using a home made diffractometer equipped with a flat film camera. The Ni-filtered CuK

radiation was used (λ = 1.54 Å).

Polymer powder samples were studied at room temperature and as a function of temperature up to the isotropization temperature.

5.7.7. X-Ray Photoelectron Spectroscopy (XPS)

XPS spectra were recorded in collaboration with Dr. A. Glisenti (University of Padova, Italy) by using a Perkin-Elmer PHI 5600 spectrometer with a monochromatic Al-Kα source (1486.6 eV) operating at 350 W. The working pressure was less than 1

Pa. The spectrometer was calibrated by assuming the binding energy (BE) of the Au 4f

line to be 84.0 eV with respect to the Fermi level. Extended spectra (survey) were collected in the range 0−1350 eV (187.85 eV pass energy, 0.4 eV step, 0.05 s/step). Detailed spectra were recorded for the following regions: C (1s) O (1s) and F (1s) (11.75 eV pass energy, 0.1 eV step, 0.1 eV s/step). The standard deviation in the BE values of the XPS line was 0.10 eV. The atomic percentage, after a Shirley type background subtraction [168], was evaluated using the PHI sensitivity factors [169]. To take into account charging problems, the C (1s) peak was considered at 285.0 eV and the peak BE differences were evaluated.

Polymer films approximately 200−300 nm thick were prepared by spin-coating a 3 wt % polymer solution on glass slides, dried under vacuum overnight, annealed at 120 °C (45

°C for P(BCL F10) and P(BCL F10-co-SiMA)) for 12 h and cooled slowly to room temperature.

XPS measurements were also carried out in collaboration with Prof. C. K. Ober (Cornell

University, Ithaca, NY). They were performed using an Axis Ultra XPS system (Kratos)

204

with a monochromatic Al KR X-ray source (1486.6 eV) operating at 225 Wunder 7.0 10

Torr vacuum. Charge compensation was carried out by injection of low-energy electrons into the magnetic lens of the electron spectrometer. The pass energy of the analyzer was set at 40 eV. The energy resolution was set at 0.1 eV with a dwell time of 500 ms. The spectra were analyzed using CasaXPS v. 2.1.9 software.

Polymer films were prepared by spin coating a 3% (w/v) polymer solution on silicon wafer, dried at 60 °C in a vacuum oven (overnight), annealed in a vacuum oven at 120 °C for 12 h and cooled slowly to room temperature.

5.7.8. Near-Edge X-Ray Absorption Fine-Structure (NEXAFS)

The NEXAFS experiments were carried out in collaboration with Prof. C. K. Ober on the NIST/Dow characterization end station on the U7A beamline at the National Synchrotron Light Source at Brookhaven National Laboratory, Upton (NY), USA.

The beamline is equipped with a toroidal mirror spherical grating monochromator that gives this beamline an incident photon energy resolution and intensity of 0.2 eV and 5x1010 photon/s, respectively, for an incident photon energy of 300 eV and a typical storage ring current of 500 mA. The X-rays are elliptically polarized, with the electric field vector E dominantly in the plane of the storage ring (polarization factor = 0.85).

The end-station is equipped with a heating/cooling stage positioned on a goniometer which controls the orientation of the sample with respect to the polarization vector of the X-rays. A differentially pumped ultrahigh vacuum compatible proportional counter is used for collecting the fluorescence yield (FY) signal. In addition, the partial-electron- yield (PEY) is collected using a channeltron electron multiplier with an adjustable entrance grid bias.

Polymer films approximately 200−300 nm thick were prepared by spin-coating a 3%

(w/v) polymer solution on silicon wafers, dried at 60 °C in a vacuum oven (overnight),

annealed in a vacuum oven at 120 °C for 12 h and cooled slowly to room temperature. To

study under-water surface reconstruction, the thermally annealed surfaces were immersed

in distilled water for 3 days at room temperature and for 12 h at 70 °C.

205

5.7.9. Grazing Incidence Small Angle X-ray Scattering (GISAXS)

The GISAXS experiments were carried out in collaboration with Prof. C. K. Ober at the G1 station of the Cornell High Energy Synchrotron Source (CHESS) using a λ = 0.124 nm X-ray beam. The beam was collimated to a height of 250 µm and a width of 250 µm by three sets of slits. Two beam stops were used in front of the detector: (i) a blade to block the direct beam and (ii) a tantalum rod 1.25 mm wide to block the intense specular reflection [92].

Images of the scattered intensity were recorded with a fiber optically coupled CCD camera (Quantum 1 by ADSC, Poway, CA). The images were corrected for background, intensity and distortion [92].

Polymer films approximately 200−300 nm thick were prepared by spin-coating a 3%

(w/v) polymer solution on silicon wafers, dried at 60 °C in a vacuum oven (overnight), annealed in a vacuum oven at 120 °C for 12 h and cooled slowly to room temperature

5.7.10. Time Of Flight Secondary Ion Mass Spectrometry (TOF-SIMS)

TOF-SIMS analysis was carried out in collaboration with Prof. A. Magnani (University of Siena) using a TRIFT III time-of-flight secondary ion mass spectrometer (Physical Electronics, Chanhassen, MN) equipped with a 69 Ga

liquid-metal primary ion source.

Positive and negative ion spectra were acquired with a pulsed, bunched 15 keV primary ion beam at 2 nA by rastering the ion beam over a 200 µm × 200 µm sample area. The primary ion dose was 10

ions/cm

to maintain static SIMS conditions. Positive mass spectra were calibrated to CH

(15.023 m/z), C

H

(27.023 m/z), C

H

(41.039 m/z) C

H

(91.005 m/z); negative data were calibrated to CH

(13.008 m/z), OH

(17.003 m/z) and C

H

(25.008 m/z).

Samples were prepared by spin coating a 3 wt % polymer solution on silicon or glass

slides. They were dried under vacuum for 12 h, annealed at 120 °C for 12 hours and

cooled slowly to room temperature.

206 5.7.11. Static Contact Angle Analysis

Contact angle measurements were carried out using an FTA200 Camtel goniometer.

Polymer films approximately 200 nm thick were prepared by spin-coating a 3 wt % polymer solution on glass supports. The rotation speed varied on the basis of the polymer, but most of the samples were prepared with a speed of 5000 rpm. Then the samples were dried under vacuum for 12 h, annealed in an oven at 120 °C (45 °C for P(BCL F10) and P(BCL F10-co-SiMA)) for 12 hours and slowly cooled to room temperature. Wetting liquids were water for HPLC analysis, artificial seawater (ASW) and Aldrich products of the highest purity available.

Liquid surface tensions of all the wetting liquid used in contact angle measurements are collected in Table 5.12.

Table 5.12. Surface tension of the testing liquids [170].

Liquid

!

"

!

"

!

"

!

"

!

"

!

"

(mJ/m

) (mJ/m

) (mJ/m

) (mJ/m

) (mJ/m

) (mJ/m

)

Water 72.8 21.8 51.0 21.8 25.5 25.5

Diiodomethane 50.8 50.8 50.8

Ethylene glycol 48.0 29.0 19.0 29.0 1.92 47.0

n-heptane 20.03 20.03 20.03

n-octane 21.38 21.38 21.38

n-decane 23.88 23.88 23.88

n-dodecane 25.13 25.13 25.13

n-hexadecane 27.62 27.62 27.62

The ASW was prepared according the following receipt:

Compound g/100 g of solution

NaCl 2.3929

Na

SO

0.4014

KCl 0.0691

NaHCO

0.0198

H

BO

0.0043

207 5.7.12. “Dynamic” Contact Angle

“Dynamic” contact angle measurements were carried out using a Dataphysics DCAT (Dynamic Contact Angle Tensiometer) 11 with immersion/withdrawal rates of 200 µm/s.

Two different experiments were made:

• Three immersion cycles at 6 mm immersion depth with dwell times between immersion and withdrawal of 10 s.

• One immersion cycle at 6 mm immersion depth with a dwell time of 1000 s followed by two immersion cycles at 12 mm and a dwell time of 10 s.

Measurements were carried out on polymer dip coated films annealed at 120 °C for 15 h and then cooled to room temperature.

HPLC water ( γ

~ 72 mN/m) was used for all the samples.

5.7.13. Atomic Force Microscopy (AFM)

AFM analysis was carried out in collaboration with Prof. C. K. Ober (Cornell University, Ithaca). Samples were imaged with a Digital Instruments Nanoscope IV with a Multimode Head. Topographic and phase contrast imagings were performed. Nanoprobe cantilevers (225 µm, Digital Instrument) were utilized. Phase contrast AFM was carried out at set-point amplitude to cantilever free-oscillation amplitude (A

/A

) ratios lower than 0.8, generally regarded as low tapping force.

Polymer films approximately 200−300 nm thick were prepared by spin-coating a 3%

(w/v) solution on silicon wafers, dried at 60 °C in a vacuum oven (overnight), annealed in a vacuum oven at 120 °C for 12 h and cooled slowly to room temperature.

5.7.14 Confocal Microscopy

Confocal microscopy was carried out in collaboration with C. Rentrop (TNO Science and Industry, Eindhoven) using a Sensofar PLµ 2300 Optical Profiler.

Measurements were performed under the following conditions:

208 Confocal objective: 20×EPI

Working distance: 4.5 mm Numerical aperture: 0.45 Field of view: 637 × 477 µm

Spatial sampling: 0.83 µm Maximum slope 21°

Repeatability: < 20 nm

Number of pixels x and y: 768 × 576 Scan height: 30 µm

Samples were prepared according to the bilayer strategy (§ 5.5).

5.7.15. Scanning Electron Microscope (SEM)

The SEM images were recorded with an electronic microscope JEOL 5600 LV operating at 13kV and 20kV. SEBS films approximately 170−200 µm thick were prepared by pressing the melted material at 230 °C. A 1.5% (w/v) toluene solution containing a blend of the amphiphilic fluorinated block copolymer and SEBS was spray coated on top of the SEBS film. Then the bilayer films were dried under vacuum and either annealed at 120

°C overnight or not annealed. Before observation, the film was fractured in liquid nitrogen and then vacuum metallized.

5.7.16. Dynamic Mechanical Analysis (DMTA)

DMTA experiments were carried out in collaboration with Prof. M. Laus (University of Piemonte Orientale) using a DMTA V (Rheometic Scientific) instrument.

Tests were performed under the following conditions:

Geometry: single cantilever bending Type of test: dynamic temperature test Heating rate: 4 °C/min

Strain: 0.1%

Strain frequency: 1 Hz

209

Samples were prepared by precipitation of the polymer blends into MeOH from chloroform solution. The obtained powders were dried under vacuum for one night and utilized to prepare specimens 20 × 5 × 2 mm by 3 size moulding.

5.7.17. Instron Thermo-Mechanical Analysis

The stress-strain up to break, the elastic modulus at 100%, 200%, 300% and 400%

deformation were measured by a 5564 Instron instrument (Instron Corporation, Canton, MA).

Polymer films were prepared as reported in § 5.7.14.

Samples were cut into microtensile test specimens and preconditioned for at least one

week at 25 °C and 50% relative humidity in a chamber containing saturated solutions of

magnesium nitrate. Samples thickness was measured with a digital micrometer. Testing

protocols were based on ASTM Standard tests D1708-93 and D638M-93. Pneumatic

grips of the testing machine were set at an initial separation of 21.6 mm. Crosshead speed

was set at 1 mm/min. At least 12 specimens for each sample were tested. Statistical

evaluations (mean, standard deviation, Student t test, and ANOVA) were performed on

the best 10 specimens from normality plot.

210