Semifluorinated diblock copolymers based on methyl methacrylate and 1 H , 1 H,2H,2H-perfluoroalkyl methacrylates were prepared by nucleophilic catalysed group transfer polymerisation. Characterisation was carried out by 'H NMR spectroscopy, differential scanning calorimetry (DSC) and gel-permeation chromatography (GPC) in toluene. The latter method revealed the formation of micelles. The surface activity of the materials was demonstrated by tensiometry using a Wilhelmy balance. Measurements on thin polymer films showed low critical surface tensions and low dispersion force contributions to the surface energy indicating the presence of the fluorinated block at the surface.

Three series of methacrylate homopolymers with oligo(hexafluoropropene oxide), (HFPO)n, side groups and copolymers based on methyl methacrylate were prepared by free radical polymerization. Each series consisted of a polymethacrylate backbone with substituted HFPO side chains of different length ranging from the corresponding tri-and tetramers to a pentamer. In case of the (HFPO)3MA copolymers, glass transition temperatures decreased linearly with increasing (HFPO)3MA content over the entire composition range. In contrast, two different regimes were distinguished for (HFPO)5MAcontaining copolymers, and also for the (HFPO)4MA homopolymer two Tg's were discerned. At low HFPO content the glass transition temperatures decreased with increasing (HFPO)5MA substitution. Above 50 mol % two glass transitions were observed, indicating microphase separation. Copolymers with only 10 mol % of (HFPO)nMA exhibited a low surface energy as is typical for highly fluorinated polymers. Dispersion force surface energies were determined by the Good-Girifalco-Fowkes-Young method and resulted in a minimum value of 11 ( 1 mN/m.

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We have recently shown that low surface energy polymeric films can be readily obtained from partially fluorinated hydroxyl-end-capped solventless liquid oligoesters by thermal curing [1]. Photocurable liquid oligoesters can be prepared by further substituting the remaining hydroxyl end groups with acrylic double bonds. A conventional photoinitiator containing 2-hydroxy-2-methylpropiophenone was used to cure the liquid oligoesters. As the fluorine content increases from 0 to about 1.57 wt %, the surface energy decreases by about 14 mN/m. The fluorine level in the outer few nanometers is significantly greater than that in the bulk, as revealed by XPS studies. The driving force for the surface segregation of fluorinated species comes from the large difference in surface energy between the oligoesters and their fluorinated counterparts.

Abstract-Random acrylic acid/hydroxyethyl methacrylate (AA/HEMA) copolymers were synthesized to study the influence of non-ionic (HEMA) structure defects introduced in poly(acrylic acid) on the complex formation with PEO (fiW 23200) at pH 3-3.5 in aqueous solution. Complex formation as studied with potentiometric titration (concentration 0.01-0.03 M monomer residues) was increasingly impeded when the molar ratio of HEMA to AA units in the polymers increased. Copolymers of AA and HEMA with molar ratios 30: 1, 10 : 1 and 3 : 1 were used in this study. It was shown that in the copolymers the number of carboxylic acid groups taking part in complexation decreased with increasing amounts of HEMA in the copolymer. However, with increasing amounts of structure defects the amount of PEO per AA residue (at equilibrium complexation) increased, suggesting less efficient packing of PEO on the acrylic copolymer chain. Copyright 0 1996

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