Characterization of PMMA-b-PDMAEMA aggregates in aqueous solutions

Abstract

Diblock amphiphilic copolymers form aggregates in some solvents. Such aggregates exhibit different morphologies, depending mainly on the polar/apolar block ratios. Aggregation of copolymers with polar block excess leads to micelle-like aggregates, known as polymeric micelles, which can be used as vehicles for drug and gene delivery, water decontamination, and catalysis. Here, we synthesized by RAFT polymerization three different polymers namely [dimethyl 2-(aminoethyl) methacrylate] (PDMAEMA), poly (methyl methacrylate) (PMMA) copolymers, and PDMAEMA-block-PMMA and characterized their aggregates by NMR spectroscopy and pH titrations. We investigated correlations between their chemical structure, aggregation behavior, protonation degree, and chain conformation in the corona. Decreased amine protonation in the copolymers reduced the electrostatic repulsion, and the apparent pK a of the amino groups approached that of isolated amine. These effects increased compactness and sizes of the polymers and their aggregates at higher pH as reflected by the increased NMR line widths.

Construction of Nanocellulose Aerogels with Mechanical Flexibility and pH-Responsive Properties via a Cross-Linker Structure Design Strategy

“…Since the pure CNF aerogel was hydrophilic, this also proved the successful grafting of PDMAEMA- co -PVTMS. As shown in Figure b, the curling of polymers under alkaline conditions caused CNF-PcoP to exhibit hydrophobic properties . As the pH decreased, the acidity used to measure the contact angle of water increases.…”

Protein fractionation of pH‐responsive brush‐modified ethylene vinyl alcohol copolymer membranes*

“…[ 28 ] A peak corresponding to the methylene protons of the PDMAEMA side chain was observed at δ = 2.5–2.6 ppm, indicating the successful modification of PDMAEMA chains on the EVAL membrane. [ 29 ]…”

“…[28] A peak corresponding to the methylene protons of the PDMAEMA side chain was observed at δ = 2.5-2.6 ppm, indicating the successful modification of PDMAEMA chains on the EVAL membrane. [29] The chemical composition of the membranes was confirmed by FTIR and XPS, as shown in Figure 2. Compared with the EVAL membrane, a new absorption peak at 1730 cm À1 corresponding to C=O bond of 2-BIB is observed in the FTIR spectrum of the EVAL-Br membrane (Figure 2A).…”

Synthesis and Properties of Cationic Gradient Brush Copolymers Carrying PEO Side Chains and Catechol Moieties

“…Potentiometric titration curves of aqueous solutions of the copolymers p(DMAEMA‐ co ‐PEOMEMA) and their quaternized derivatives p(QDMAEMA‐ co ‐PEOMEMA) were produced by dissolving the copolymers in deionized water, adding an excess of 1 m HCl to reach pH ≈2, and titrating with 0.1 m NaOH solution ( Figure . The titration curves of DMAEMA copolymers usually have two endpoints: [ 45 ] the first one corresponding to the titration of excess HCl and the second one corresponding to the complete deprotonation of amino groups. In the studied case, they are almost imperceptible.…”