Dataset Information

Synthesis and Phase Behavior of Poly(N-isopropylacrylamide)-b- Poly(L-Lysine Hydrochloride) and Poly(N-Isopropylacrylamide- co-Acrylamide)-b-Poly(L-Lysine Hydrochloride).

ABSTRACT: The synthesis of poly(N-isopropylacrylamide)-b-poly(L-lysine) and poly(N- isopropylacrylamide-co-acrylamide)-b-poly(L-lysine) copolymers was accomplished by combining atom transfer radical polymerization (ATRP) and ring opening polymerization (ROP). For this purpose, a di-functional initiator with protected amino group was successfully synthetized. The ATRP of N-isopropylacrylamide yielded narrowly dispersed polymers with consistent high yields (~80%). Lower yields (~50%) were observed when narrowly dispersed random copolymers of N-isopropylacrylamide and acrylamide where synthesized. Amino-terminated poly(N-isopropylacrylamide) and poly(N-isopropylacrylamide- co-acrylamide) were successfully used as macroinitiators for ROP of N?-carbobenzoxy-L- lysine N-carboxyanhydride. The thermal behavior of the homopolymers and copolymers in aqueous solutions was studied by turbidimetry, dynamic light scattering (DLS) and proton nuclear magnetic resonance spectroscopy (¹H-NMR).

SUBMITTER: Spasojevic M

PROVIDER: S-EPMC5455825 | biostudies-other | 2014 Jul

REPOSITORIES: biostudies-other

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Publications

Synthesis and Phase Behavior of Poly(N-isopropylacrylamide)-b- Poly(L-Lysine Hydrochloride) and Poly(N-Isopropylacrylamide- co-Acrylamide)-b-Poly(L-Lysine Hydrochloride).

Spasojević Milica M Vorenkamp Joop J Jansen Mark R P A C S MRPACS de Vos Paul P Schouten Arend Jan AJ

Materials (Basel, Switzerland) 20140722 7

The synthesis of poly(N-isopropylacrylamide)-b-poly(L-lysine) and poly(N- isopropylacrylamide-co-acrylamide)-b-poly(L-lysine) copolymers was accomplished by combining atom transfer radical polymerization (ATRP) and ring opening polymerization (ROP). For this purpose, a di-functional initiator with protected amino group was successfully synthetized. The ATRP of N-isopropylacrylamide yielded narrowly dispersed polymers with consistent high yields (~80%). Lower yields (~50%) we ...[more]

PMID: 28788130

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Project description:Thermoresponsive poly((N,N-dimethyl acrylamide)-co-(N-isopropyl acrylamide)) (P(DMA-co-NIPAM)) copolymers were synthesized via reversible addition-fragmentation chain transfer (RAFT) polymerization. The monomer reactivity ratios were determined by the Kelen-Tüdős method to be rNIPAM = 0.83 and rDMA = 1.10. The thermoresponsive properties of these copo-lymers with varying molecular weights were characterized by visual turbidimetry and dynamic light scattering (DLS). The copolymers showed a lower critical solution temperature (LCST) in water with a dependence on the molar fraction of DMA in the copolymer. Chaotropic and kosmotropic salt anions of the Hofmeister series, known to affect the LCST of thermoresponsive polymers, were used as additives in the aqueous copolymer solutions and their influence on the LCST was demonstrated. Further on, in order to investigate the thermoresponsive behavior of P(DMA-co-NIPAM) in a confined state, P(DMA-co-NIPAM)-b-PS diblock copolymers were prepared via polymerization induced self-assembly (PISA) through surfactant-free RAFT mediated emulsion polymerization of styrene using P(DMA-co-NIPAM) as the macromolecular chain transfer agent (mCTA) of the polymerization. As confirmed by cryogenic transmission electron microscopy (cryoTEM), this approach yielded stabilized spherical micelles in aqueous dispersions where the PS block formed the hydrophobic core and the P(DMA-co-NIPAM) block formed the hydrophilic corona of the spherical micelle. The temperature-dependent behavior of the LCST-type diblock copolymers was further studied by examining the collapse of the P(DMA-co-NIPAM) minor block of the P(DMA-co-NIPAM)-b-PS diblock copolymers as a function of temperature in aqueous solution. The nanospheres were found to be thermosensitive by changing their hydrodynamic radii almost linearly as a function of temperature between 25 °C and 45 °C. The addition of kosmotropic salt anions, as a potentially useful tuning feature of micellar assemblies, was found to increase the hydrodynamic radius of the micelles and resulted in a faster collapse of the micelle corona upon heating.

Dataset Information

Synthesis and Phase Behavior of Poly(N-isopropylacrylamide)-b- Poly(L-Lysine Hydrochloride) and Poly(N-Isopropylacrylamide- co-Acrylamide)-b-Poly(L-Lysine Hydrochloride).

Publications

Synthesis and Phase Behavior of Poly(<i>N</i>-isopropylacrylamide)-b- Poly(L-Lysine Hydrochloride) and Poly(<i>N</i>-Isopropylacrylamide- co-Acrylamide)-b-Poly(L-Lysine Hydrochloride).

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