Self-Assembly of Monotethered Single-Chain Nanoparticle Shape Amphiphiles

Abstract

Shape amphiphiles with distinct shapes and amphiphilic properties can be used as fundamental building blocks in the fabrication of novel structures and advanced materials. In this research synthesis and selfassembly of monotethered single-chain nanoparticle shape amphiphiles are reported. Poly(2-(dimethylamino)ethyl methacrylate)-block-polystyrene (PDMAEMA-b-PS) was synthesized by two-step reversible addition− fragmentation chain transfer (RAFT) polymerization. The PDMAEMA blocks were intramolecularly cross-linked by 1,4-diiodobutane (DIB) at significantly low concentrations, and PS-tethered PDMAEMA single-chain nanoparticles were prepared. Gel permeation chromatograph, 1 H NMR and transmission electron microscopy results all indicated successful synthesis of the structures. The controlled self-assembly of the shape amphiphiles in selective solvents was investigated. Depending on the size of the single-chain nanoparticles, the shape amphiphiles self-assemble into strawberry-like micelles, a structure with single-chain nanoparticles in the corona and PS in the core, or vesicles in aqueous solutions. Similar to the self-assembled structures in aqueous solution, the morphology of the aggregates in methanol changes from micellar structure to vesicular structure with the decrease of the PDMAEMA single-chain nanoparticles size. In cyclohexane, the shape amphiphiles self-assemble into bunchy micelles with single-chain nanoparticles in the cores and linear PS in the coronae.

A brief user's guide to single-chain nanoparticles

“…41 Similar results were obtained by Pomposo et al in a recent publication. AFM allows for the dimensional analysis of SCNPs, but TEM results have had better diameter correlation with DLS data than AFM, most likely due to the error resulting from the broadness of the AFM tip.…”

“…41 The p(DMAEMA) block was collapsed using a quaternization reaction of the tertiary amine with 1,4diiodobutane. 41 The p(DMAEMA) block was collapsed using a quaternization reaction of the tertiary amine with 1,4diiodobutane.…”

Intramolecular Cross-Linking Methodologies for the Synthesis of Polymer Nanoparticles

“…140 Wen et al exploited the use of quaternization chemistry to prepare tadpole-like single-chain nanoparticles that are capable of selfassembling to form micelles. 141 These tadpole-like single-chain nanoparticles are usually prepared by the collapse of one block of a diblock polymer (vide supra). In their work, Wen et al used RAFT polymerization-derived poly(2-(dimethylamino)ethyl methacrylate)-block-polystyrene (PDMAEMA-b-PS) as the precursor polymer.…”

Amphiphilic Nanocapsules Entangled with Organometallic Coordination Polymers for Controlled Cargo Release

“…The polymers self-assembled into vesicles in aqueous media depending on their compositions. 26 Armes and co-workers in situ synthesized amphiphilic PHPMA-b-PBzMA vesicles via RAFT alcoholic dispersion polymerization (PHPMA, poly(2-hydroxypropyl methacrylate; PBzMA, poly(benzyl methacrylate)), which depended on chain length of hydrophobic segments. 27 Du and co-workers prepared genus vesicles through self-assembly of PMEO 2 MA-b-PTA block copolymers (PMEO 2 MA, poly(2-(2-methoxyethoxy)ethyl methacrylate), PTA, poly(2-(tertbutylaminoethyl)methacrylate)) in DMF/water mixture.…”