Characterization of Diblock Copolymers by Capillary Electrophoresis: From Electrophoretic Mobility Distribution to Distribution of Composition

Abstract

Free solution capillary-electrophoresis (CE) is a powerful separation technique for the characterization of diblock copolymers. In this work, four series of double-hydrophilic anionic and cationic block copolymers, namely, poly(acrylamide)-block-poly(acrylic acid) (PAM-b-PAA), poly(acrylamide)-block-poly((3-acrylamidopropyl)trimethylammonium chloride) (PAM-b-PAPTAC), poly(ethylene oxide)-block-poly(acrylic acid) (PEO-b-PAA) and poly(poly(ethylene glycol) methyl ether acrylate)-block-poly(acrylic acid) (P(PEGA)-b-PAA), were synthesized by reversible additionfragmentation chain transfer (RAFT) polymerization and characterized by CE. The electrophoretic mobility distributions of the copolymers were transformed into distributions of composition ratio by introducing a retardation parameter, Xexp,, that represents the hydrodynamic drag retardation due to the neutral block of the copolymer. A linear correlation between Xexp and the ratio of the degrees of polymerization of each blocks was experimentally established and was consistent with the model of electrophoretic mobility of composite macromolecules with hydrodynamic coupling. Finally, the comparison of the distributions between the different copolymer families was significantly improved by considering the distributions in composition ratio compared to the electrophoretic mobility distributions, since it takes into account the differences in solvation, expansion and drag force according to the chemical nature of the blocks.

Integrated Process for Structuring and Functionalizing Ordered Mesoporous Silica to Achieve Superprotonic Conductivity

“…The synthesis of the DHBC was adapted from previous work − and performed as follows: P­(APEO) 25 -DDMAT (15.02 g, 1.22 mmol, 1 equiv), SSNa (6.92 g, 30.3 mmol, 24.3 equiv), ACPA (0.0702 g, 0.25 mmol, 0.2 equiv), and distilled water (9.15 g) were introduced in a round-bottom flask and stirred (solid content = 70%). The mixture was degassed with nitrogen bubbling for 30 min under magnetic stirring.…”

“…The DP and conversion were determined by 1 H NMR (DP P(SSNa) = 21.4, monomer conversion >99.9%, M n, P(APEO)-b-P(SSNa) = 16,954 g mol −1 , Figure S4). Due to the polyionic structure, no SEC analysis was realized on this DHBC, but a capillary-electrophoresis experiment was performed (Figure S5), according to conditions previously reported, 30 to check the presence of the covalent link between the two blocks in synthesized P(APEO) 25 -b-P(SSNa) 21 -DDMAT.…”

Weak Polyelectrolytes as Nanoarchitectonic Design Tools for Functional Materials: A Review of Recent Achievements

“…Conversely, changing the surface charge density of such micelles by pH-induced protonation of weak polyelectrolyte blocks controlled the stability or aggregation behavior of PS- b -P2VP- b -PEO [ 227 ], PB- b -P2VP- b -PMAA [ 228 ], and PCL- b -PEO- b -P2VP)[ 229 ] micelles. In contrast, when BCPs combine weak polyion blocks with hydrophobic blocks, they can micellize on complexation of their polyelectrolyte block with oppositely charged partners (polycations, drugs, multivalent cations) as reported for poly(ethylene glycol-b-2-(dimethylamino)ethylmethacrylate) (PEG- b -PDMAEMA), poly(acrylic acid- b -ethylene oxide) (PAA- b -PEO) and PNIPAM- b -PAA [ 230 , 231 ]. Such micelles recently found applications as drug vectors and sol-gel structure directing agents with pH-triggered stability [ 232 ].…”

Dual control of external surface and internal pore structure of small ordered mesoporous silica particles directed by mixed polyion complex micelles

“…Three double-hydrophilic block copolymers of same molecular weights were synthesized. PEO227-b-PAA40, PAPEO20-b-PAA40 and PAM140-b-PAA40 were synthesized by aqueous RAFT or MADIX polymerization following the procedure published by Phimphachanh et al [66] The degrees of polymerization of the blocks were determined from 1 H NMR and SEC analyses. For all DHBC, the molecular weight of the neutral block (PEO, PAPEO or PAM) is 10000 g.mol -1 and the molecular weight of the PAA block is 2880 g.mol -1 .…”