Self-assembly of poly(vinylidene fluoride)-block-poly(2-(dimethylamino)ethylmethacrylate) block copolymers prepared by CuAAC click coupling

Abstract

Poly(vinylidene fluoride) (PVDF) is a very important fluoropolymer which possesses remarkable physico-chemical properties such as high thermal and chemical resistances as well as ferroelectricity, for example. To date, only iodine transfer polymerization and RAFT polymerization have enabled the preparation of well-defined PVDF and of some PVDF-based block copolymers (BCPs). However, these reversible deactivation radical polymerization techniques suffer from undesired reactions which impair the synthesis of a wide range of PVDF-containing BCPs. Here, unprecedented poly(vinylidene fluoride)-block-poly(2-(dimethylamino)ethylmethacrylate) (PVDF-b-PDMAEMA) BCPs were prepared by CuAAC click coupling of azide-functionalized PVDF synthesized by RAFT polymerization and alkyne-functionalized PDMAEMA synthesized by ATRP. This strategy was quite efficient and afforded three relatively well-defined BCPs (PVDF₄₀-b-PDMAEMA₂₃, PVDF₄₀-b-PDMAEMA₆₉, PVDF₄₀-b-PDMAEMA₁₆₂, Đ < 1.55). These amphiphilic BCPs were self-assembled in water at pH 2, 8 (native pH) and 10. The morphologies obtained were mainly polydisperse (20–500 nm), roughly spherical aggregates. However, at pH 8, PVDF₄₀-b-PDMAEMA₆₉ also formed micrometer-long rigid cylindrical micelles. These morphologies are likely the first examples of PVDF-containing BCP nanostructures produced by crystallization-driven self-assembly.