Polymerization-induced self-assembly driving chiral nanostructured materials

Abstract

To prepare chiral nanostructures coated with bioactive molecules, a side-chain amino acid containing macromolecular chain transfer agent (macroCTA), poly(Boc-L-alanine methacryloyloxyethyl ester) (PBLAEMA), has been used as the steric stabilizer for the reversible addition-fragmentation chain transfer (RAFT) mediated dispersion polymerization of benzyl methacrylate (BzMA) in methanol at 65°C. Gel permeation chromatography (GPC) analysis confirmed an efficient and well-controlled block copolymerization. A full spectrum of morphologies spanning spherical micelles, worm like micelles, fibres and vesicles could be attained by tuning (i) the length of the solvophobic block and (ii) the total solid content at which the block copolymerization is performed. Interestingly, a purely fibre phase morphology formed a thermoresponsive gel at room temperature above a critical fibre entanglement concentration, which underwent degelation upon heating because of the morphological transformation from anisotropic fibre to isotropic sphere. In actual fact, twisted nano-fibres have been formed through the hierarchical selfassembling of polymerization induced self-assembly (PISA) generated macromolecules in the gel state.Circular dichroism (CD) spectroscopy was used to elucidate chiroptical properties. Additionally, a high demanding wrinkle surface has been constructed preliminarily from this copolymer dispersion solution.Successful Boc-group expulsion facilitates the disassembly of vesicles to either worms or spheres with an appreciable cationic character below pH 7.0 as revealed by aqueous electrophoresis studies. Though the creation of nano-objects through PISA is well-known, fabricating chiral nanostructures with reactive handles and their hierarchical self-organization to have functional architectures is a less explored area. In this present work we were able to hybridize PISA, chirality and hierarchical self-assembling. † Electronic supplementary information (ESI) available: GPC chromatograms, CD spectra, 1 H NMR spectrum and DLS size distributions of various block copolymers. See

Side‐Chain Amino‐Acid‐Derived Cationic Chiral Polymers by Controlled Radical Polymerization

“…Polymerization‐induced self‐assembly is a convenient way of making a myriad of macromolecular nanoobjects depending upon the solvophilic/solvophobic volume ratio by using living radical polymerizations. A full spectrum of morphologies spanning spherical micelles, worm‐like micelles, fibers, vesicles, etc., could be attained by changing reaction parameters (Figure ) …”

“…A full spectrum of morphologies spanning spherical micelles, worm-like micelles, fi bers, vesicles, etc., could be attained by changing reaction parameters ( Figure 6 ). [ 118 ] In addition, we have synthesized different side-chain dipeptidebased homopolymers and their corresponding block copolymers with mPEG 2k . Self-assembly of those amphiphilic block copolymers and double hydrophilic block copolymers were investigated in detail.…”

Helicity of perfluoroalkyl chains controlled by the self‐assembly of the Ala‐Ala dipeptides

“…Studying chiral transfer phenomenon can provide guidance for the directional design of chiral nanostructure materials. Self‐assembly is an ideal way to prepare chiral materials . H‐bonding plays a major role in the process of chirality transfer .…”

“…Selfassembly is an ideal way to prepare chiral materials. 29,30 H-bonding plays a major role in the process of chirality transfer. 31,32 Wei et al reported that chirality information can be transferred from conjugated molecules to structures using π-conjugated molecules as functional building blocks.…”

Surface functionalized nano‐objects from oleic acid‐derived stabilizer via non‐polar RAFT dispersion polymerization

“…In addition, different polysaccharide‐based functional polymeric nano‐particles were reported through PISA process . We also have used a side‐chain alanine containing methacrylate polymer as a steric stabilizer and polymerization control agent for RAFTDP of benzyl methacrylate (BzMA) to obtain diverse sets of block copolymer nano‐objects in methanol …”