Copper(I)-mediated living radical polymerization was used to synthesize amphiphilic block copolymers of poly(n-butyl methacrylate) [P(n-BMA)] and poly [(2dimethylamino)ethyl methacrylate] (PDMAEMA). Functionalized bromo P(n-BMA) macroinitiators were prepared from monofunctional, difunctional, and trifunctional initiators: 2-bromo-2-methylpropionic acid 4-methoxyphenyl ester, 1,4-(2Ј-bromo-2Јmethyl-propionate)benzene, and 1,3,5-(2Ј-bromo-2Ј-methylpropionato)benzene. The living nature of the polymerizations involved was investigated in each case, leading to narrow-polydispersity polymers for which the number-average molecular weight increased fairly linearly with time with good first-order kinetics in the monomer. These macroinitiators were subsequently used for the polymerization of (2-dimethylamino)ethyl methacrylate to obtain well-defined [P(n-BMA) x -b-PDMAEMA y ] z diblock (15,900; polydispersity index ϭ 1.60), triblock (23,200; polydispersity index ϭ 1.24), and star block copolymers (50,700; polydispersity index ϭ 1.46). Amphiphilic block copolymers contained between 60 and 80 mol % hydrophilic PDMAEMA blocks to solubilize them in water. The polymers were quaternized with methyl iodide to render them even more hydrophilic. The aggregation behavior of these copolymers was investigated with fluorescence spectroscopy and dynamic light scattering. For blocks of similar comonomer compositions, the apparent critical aggregation concentration (cac ϭ 3.22-7.13 ϫ 10 Ϫ3 g L Ϫ1 ) and the aggregate size (ca. 65 nm) were both dependent on the copolymer architecture. However, for the same copolymer structure, increasing the hydrophilic PDMAEMA block length had little effect on the cac but resulted in a change in the aggregate size.

An ongoing challenge in polymer science is the preparation of materials with specific surface properties which differ from that of the bulk, for example, hydrophobicity, wettability, chemical resistance, adhesion, or biocompatibility, while retaining the advantageous mechanical properties of the bulk polymer. We have explored the use of multi-end-functionalized polymer additives which undergo rapid adsorption to a surface or interface as an efficient method of modifying surface properties. Aryl ether moieties bearing up to four C 8 F 17 groups have been used as initiators in the copper-mediated living radical polymerization of both styrene and methyl methacrylate, and the resulting polymers have been used as additives to render the surfaces of the corresponding bulk polymers hydrophobic and oleophobic. When such an additive consisting of a polystyrene chain with a molecular weight of ∼10 000 g mol -1 end-capped with four C 8 F 17 groups is present (in a matrix of polystyrene) at levels between 5 and 10 wt %, near PTFE-like surface properties result.

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Dendritically fluorocarbon‐functionalized poly(methyl methacrylate) (PMMA) has been explored as a robust surface‐modifying additive in PMMA blends. These functionalized materials, denoted FxPMMAy, where x is the number of C8F17 fluorocarbon groups per dendron connected to a PMMA chain of y kg/mol, have been synthesized by living radical polymerization. These materials adsorb efficiently to the surfaces of their blends with unfunctionalized PMMA, resulting in increased hydrophobicity and lipophobicity. Contact‐angle goniometry has indicated a substantial reduction in the surface energy toward polytetrafluoroethylene‐like surface properties in the case of pure F4PMMA8.6 and substantial, but incomplete fluorocarbon surface coverage at a lower FxPMMAy concentration. The partial coverage has been confirmed by Rutherford backscattering and, together with the weak dependence of the surface modification on the FxPMMAy structure, indicates incomplete equilibrium of the surface adsorption. The modified surfaces are quite durable with respect to abrasion under water but are progressively eroded when the double‐wipe test is carried out with acetone. FxPMMAy, dispersed in the remaining film, acts as a reservoir of spare functional groups, from which the damaged surface may be replenished, leading to the recovery of the modified surface properties. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007