Association, emulsifying, and solubilization properties of amphiphilic hyperbranched poly(acrylic acid) with short polystyrene stickers

Abstract

Amphiphilic hyperbranched copolymer chains made of large hyperbranched poly(acrylic acid) cores grafted with short polystyrene stickers (HB-PAA n -g-PS n 1 1 ) with different n values (n 5 1, 10, 47) were well prepared and confirmed by size exclusion chromatography, Fourier transform infrared spectroscopy and 1 H nuclear magnetic resonance. The study on the interchain association behavior of these amphiphilic chains indicates that larger HB-(PAA) n -g-(PS) n 1 1 copolymer chains have a less tendency to undergo interchain association. Moreover, the simple vial-inversion and rheological experiments show that the apparent critical gel concentration (C g ) decreases with n, but no sol-gel transition was observed for triblock PS-PAA-PS even when the concentration is up to 200 g L 21. Further transmission electron microscopy study of the latex particles prepared with HB-(PAA) n -g-(PS) n 1 1 as surfactant reveals that the latex particles are spherical and narrowly dispersed; while the measured latex particle number (N p ) indicates the surfactant efficiency of HB-(PAA) 47 -g-(PS) 48 is poorer than that of triblock PS-PAA-PS (n 5 1). Finally, pyrene solubilization measurement shows the solubilization efficiency of HB-(PAA) ng-(PS) n 1 1 copolymers decreases with n, consistent with the previous observed interchain association result. The present study demonstrates that both the chain topology and the styrene weight fraction dominates the final solution properties of amphiphilic HB-(PAA) n -g-(PS) n 1 1 chains in aqueous solution.

Formation of long sub-chain hyperbranched poly(methyl methacrylate) based on inhibited self-cyclization of seesaw macromonomers

“…Moreover, disubstituted chain ends of the PMMA chain would tend towards steric hindrance to suppress the intramolecular self-cyclization of alkynyl-(PMMA-N 3 ) 2 compared with monosubstituted alkynyl-(PSt-N 3 ) 2 and alkynyl-(PtBA-N 3 ) 2 . 36,46,53 The influence of steric hindrance on the copper-catalyzed azide-alkyne click reaction has been reported in the preparation of ferrocene-labelled steroids with a series of azido-functionalized androstanes. 39 A considerably low reactivity of 6β-azido-androstane towards ethynylferrocene was confirmed due to the steric hindrance brought by the bulky ferrocene moiety.…”

Conformational Transition and Interchain Association of Hypergraft HB-PS-g-PtBA Copolymer Chains with Varied Copolymer Compositions and Block Lengths in a Selective Solvent

“…Due to the rich solution phase behavior, block copolymers have been extensively studied in many fields, such as drug delivery, electronic materials, and functional coatings, to name but a few. Over the past decades, much attention has been paid to the understanding of how the structural feature affects the fundamental solution phase behavior, such as the intrachain collapse, − interchain association, − and interchain assembly. − …”

Hyperbranched block copolymer from AB2 macromonomer: Synthesis and its reaction‐induced microphase separation in epoxy thermosets

“…Hedrick and coworkers reported the synthesis of a series of hyperbranched block copolymers by using the polycondensation copolymerization of different AB 2 macromonomers bearing terminal carboxyl and hydroxyl groups. More recently, Li et al reported the synthesis of amphiphilic hyperbranched block copolymers via a grafting‐to approach. They first synthesized the hyperbranched poly(acrylic acid) (or polystyrene) homopolymers with a great number of azido end groups; then mono‐alkynyl‐terminated polystyrene (PS) [or poly(acrylic acid)] was grafted onto the hyperbranched polymer via a copper‐catalyzed Huisgen 1,3‐dipolar cycloaddition reaction.…”