Phenylalanine‐Tethered pH‐Responsive Poly(2‐Hydroxyethyl Methacrylate)

Abstract

A series of pH-responsive random copolymers comprised of 2-hydroxyethyl methacrylate (HEMA) and tertbutyl carbamate (Boc)-protected phenylalanine methacryloyloxyethyl ester (Boc-Phe-EMA) were synthesized via reversible addition-fragmentation chain transfer (RAFT) polymerization in N,N'-dimethylformamide (DMF) at 70°C. The synthesized copolymers were comprehensively characterized using a combination of techniques, including 1 H NMR, FT-IR spectroscopy and size exclusion chromatography (SEC). Reactivity of each monomers towards controlled radical polymerization was evaluated by determining the reactivity ratios by virtue of extended Kelen-Tüdös method at high conversions revealed the higher reactivity of non-modified HEMA (r HEMA = 1.03) in contrast to Boc-Phe-EMA (r Boc-Phe-EMA = 0.48). Furthermore, the expulsion of the Boc-groups resulted copolymers with ionizable pendant primary ammonium and hydroxyl groups. To understand the glass transition behaviours of homo-and co-polymers, differential scanning calorimetric (DSC) measurements were carried out. The effect of HEMA content on the pH-sensitivity of the copolymers in aqueous medium was investigated through turbidity measurements. Finally, the counteranion exchange from trifluoroacetate to chloride provided copolymers with enhanced water solubility and unaltered phase transition pH.

Fast and scalable production of crosslinked polyimide aerogel fibers for ultrathin thermoregulating clothes

“…According to the FTIR spectrum, compared with pure PI, additional peaks of -CH 3 bonds at 2924 cm −1 and -CH 2 bonds at 2860 cm −1 appear for PPI-x samples, suggesting effective grafting of HEMA onto the PI 26 , 27 . The aliphatic hydrocarbon chains of HEMA in the PPI are indicated by the peaks at about 6.06 ppm, 4.6 ppm, and 4.45 ppm in the 1 H NMR spectra, which correspond to H 21 , H 22 , and H 24 28 , respectively. The practical grafting ratio calculated by 1 H NMR are 24.8%, 47.9% and 76.0% for PPI-25, PPI-50 and PPI-100, respectively, which are comparable with the theoretical grafting ratio (Supplementary Fig.…”

Antioxidant Polymers with Phenolic Pendants for the Mitigation of Cellular Oxidative Stress

“…44 The methacrylamide monomers namely M1 (with Phe group), M2 (with tyrosyl group), M3 (with catechol group), and M4 (with gallol group) were synthesized with high yield through different synthetic routes (Schemes S1−S4). 45,46 The intermediates as well as monomers were characterized by nuclear magnetic resonance (NMR) spectroscopy and high-resolution mass spectrometry (HRMS; Figures S1−S12). All the monomers exhibited characteristic peaks for the vinyl unit, the aromatic ring, and the protected groups in the 1 H NMR spectra, and the integration of different protons in their respective chemical structure was also well-matched.…”

Methyl Methacrylate-Based Copolymers: Recent Developments in the Areas of Transparent and Stretchable Active Matrices

“… 17 In addition, many alkyl methacrylate polymers act as additives to enhance the rheological characteristics of lubricants. 18 Methacrylate homopolymers such as, poly(2-hydroxyethyl methacrylate), 19 , 20 poly(2-phenylethyl methacrylate), 21 2-(acetoacetoxy)ethyl methacrylate, 22 and poly(benzyl methacrylate), 23 are widely used in the development of hydrogels, medical implants, and adhesives, respectively. However, the most widely used and well-known alkyl methacrylate polymer is PMMA.…”