Precise synthesis and surface structures of architectural per- and semifluorinated polymers with well-defined structures

This article reviews the synthesis by methodologies based on living/controlled polymerization, of well-defined perfluorinated and semifluorinated (FL) homopolymers, chain-end-functionalized polymers with FL group(s), block copolymers having FL segment(s), chain-end-multifunctionalized polymers with a definite number of FL groups, and star-branched and dendrimer-like hyperbranched polymers having FL segment(s). Most of the FL groups and FL segments comprise perfluoroalkyl and/or semifluoroalkyl side chains, represented as a CF3(CF2)(m-1)(CH2)(n) moiety. In the FL polymers herein presented, except for FL homopolymers, such FL components are chemically linked to non-FL polymer chains and readily separated at the molecular level, followed by self-organization, to form a variety of nanoscale molecular assemblies at the surface of a film, in bulk, and in solution. The FL components possess many unique and interesting characteristics, such as remarkably low surface energies, low friction coefficients, strong incompatibility with conventional hydrocarbon-based polymers, high thermal stability, chemical inertness, and phenyl-free liquid crystalline formation. The surface, solution, and bulk properties of polymer structures including FL units reflect these characteristics of the self-organization of polymers with FL components is of particular interest. Moreover, non-FL polymer chains may enhance the solubility of FL polymers, and render molecular assemblies more changeable in shape, form, and size. Recent reports on these subjects are presented in this review. (C) 2007 Elsevier Ltd. All rights reserved.