Self‐assembly of block copolymers with an alkoxysilane‐based core‐forming block: A comparison of synthetic approaches

Abstract

Polymerization‐induced self‐assembly (PISA) has become the preferred method of preparing self‐assembled nano‐objects based on amphiphilic block copolymers. The PISA methodology has also been extended to the realization of colloidal nanocomposites, such as polymer–silica hybrid particles. In this work, we compare two methods to prepare nanoparticles based on self‐assembly of block copolymers bearing a core‐forming block with a reactive alkoxysilane moiety (3‐(trimethoxysilyl)propyl methacrylate, MPS), namely (i) RAFT emulsion polymerization using a hydrophilic macroRAFT agent and (ii) solution‐phase self‐assembly upon slow addition of a selective solvent. Emulsion polymerization under both ab initio and seeded conditions were studied, as well the use of different initiating systems. Effective and reproducible chain extension (and hence PISA) of MPS via thermally initiated RAFT emulsion polymerization was compromised due to the hydrolysis and polycondensation of MPS occurring under the reaction conditions employed. A more successful approach to block copolymer self‐assembly was achieved via polymerization in a good solvent for both blocks (1,4‐dioxane) followed by the slow addition of water, yielding spherical nanoparticles that increased in size as the length of the solvophobic block was increased. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018, 56, 420–429

Interfacial crosslinking of self‐assembled triblock copolymer nanoparticles via alkoxysilane hydrolysis and condensation

“…Recently, our group has developed an approach toward the preparation of hybrid colloidal nanocomposites via PISA and sol–gel chemistry, utilizing a reactive alkoxysilane‐functional methacrylate . A commercially available alkoxysilane, namely 3‐(trimethoxysilyl)propyl methacrylate (MPS), has been used both as the solvophilic and solvophobic block in block copolymer nanoparticle design, followed by the controlled growth of silica domains via hydrolysis and condensation of a silica precursor (TEOS).…”

Investigation of segmental reorganization within amphiphilic block polymer nanoparticles derived from shell crosslinked micelle templates: Shell crosslinked knedel‐like inversion

“…In the 1990's, supramolecular assembly of amphiphilic block polymers in selective solvents, which thermodynamically favor one of the blocks, emerged as a general technique for the generation of micellar structures having morphological diversity. [1][2][3][4][5][6][7] Over the past couple of decades, tuning the composition and architecture of the block polymer building blocks [8][9][10][11][12][13][14][15][16] and incorporating environmentally responsive chemical functionalities have been shown to promote morphological switching and lead to enhanced behaviors and functions. [17][18][19][20][21][22][23][24] The covalent stabilization of micelles and other supramolecular assemblies was also recognized as a powerful method, analogous to that utilized in biology, 25 for the rapid and large-scale preparation of intricate and stable nanostructured materials.…”