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.