Synthesis and self-assembly of stimuli-responsive amphiphilic block copolymers based on polyhedral oligomeric silsesquioxane

Abstract

A novel POSS‐containing methacrylate monomer (HEMAPOSS) was fabricated by extending the side chain between polyhedral oligomeric silsesquioxane (POSS) unit and methacrylate group, which can efficiently decrease the steric hindrance in free‐radical polymerization of POSS‐methacrylate monomer. POSS‐containing homopolymers (PHEMAPOSS) with a higher degree of polymerization (DP) can be prepared using HEMAPOSS monomer via reversible addition–fragmentation chain transfer (RAFT) polymerization. PHEMAPOSS was further used as the macro‐RAFT agent to construct a series of amphiphilic POSS‐containing poly(N, N‐dimethylaminoethyl methacrylate) diblock copolymers, PHEMAPOSS‐b‐PDMAEMA. PHEMAPOSS‐b‐PDMAEMA block copolymers can self‐assemble into a plethora of morphologies ranging from irregular assembled aggregates to core‐shell spheres and further from complex spheres (pearl‐necklace‐liked structure) to large compound vesicles. The thermo‐ and pH‐responsive behaviors of the micelles were also investigated by dynamic laser scattering, UV spectroscopy, SEM, and TEM. The results reveal the reversible transition of the assembled morphologies from spherical micelles to complex micelles was realized through acid‐base control. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014, 52, 2669‐2683

Polyisobutylene containing organic/inorganic hybrid block copolymers and their crystalline behavior

“…35, 11.07, 12.21, 19.34, and 25.19 o in the WAXS curves of PIB-b-PMA-POSS block copolymers. Aggregation of POSS spheres in the block copolymer 50 to the ordered crystalline structures will offer a new opportunity to design better composite materials having biocompatible PIB segment.…”

Polyhedral Oligomeric Silsesquioxane Hybrid Polymers: Well‐Defined Architectural Design and Potential Functional Applications

“…Based on the high flexibility of self‐assembly behavior in POSS‐hybrid polymers, POSS can also serve as a template for preparing hollow‐structured micelles. As presented by Zhang et al, PHEMAPOSS‐ b ‐P(DMAEMA‐ co ‐CMA) 24 self‐assembles in aqueous solution into spherical micelles with POSS cores and stimuli‐responsive shells . Hollow polymeric capsules have been obtained after etching POSS cores in the micelles, which could be further applied for the encapsulation and release of tetraphenylporphyrin tetrasulfonic acid hydrate (TPPS) in PDT, being also responsive to pH and redox potential.…”

Synthesis and assembly of polyhedral oligomeric silsesquioxane end-capped amphiphilic polymer to enhance the fluorescent intensity of tetraphenylethene

“…A typical POSS molecule owns a three-dimensional cage-like structure composed of silicon and oxygen atoms with a diameter in the range of 1-3 nm [5,6]. The chemical formula of POSS is (RSiO 1.5 ) n , where n is commonly 6, 8 or 10 [7][8][9]. POSS is biocompatible and mechanically stable.…”