Exploration of the modification-induced self-assembly (MISA) technique and the preparation of nano-objects with a functional poly(acrylic acid) core

Abstract

The hydrolysis-based post-polymerization modification method was introduced into the self-assembly process and a modification-induced self-assembly (MISA) technique was presented. The diblock copolymer poly(styrene)-b-poly(tert-acrylate) (PS-b-PtBA) was employed as a precursor, trifluoroacetic acid (TFA) was used as a modifying agent, and toluene was used as the solvent. With the gradual hydrolysis of the PtBA block, the generated poly(acrylic acid) (PAA) block showed reduced solubility in toluene and induced an in situ self-assembly process. By modulating the degree of polymerization of the PtBA block (DP_PtBA), weight solids content (up to 15.0% w/w), the morphological evolution of the MISA process was investigated, and a series of spherical, worm-like and vesicular nano-objects were obtained. By modulating the topology of copolymers, such as the triblock copolymers PS-b-PtBA-b-PS and PtBA-b-PS-b-PtBA and star-shaped copolymers Star-(PtBA-b-PS)₄ and Star-(PS-b-PtBA)₄, it was observed that the topology also played an important role in the self-assembly behavior. As an alternative route to self-assembly, the MISA technique comprehensively combined the merits of the conventional self-assembly and the recently developed polymerization-induced self-assembly (PISA) techniques.