Synthesis and thermoassociative properties in aqueous solution of graft copolymers containing poly( N -isopropylacrylamide) side chains

Thermoassociative graft copolymers based on poly(N-isopropylacrylamide): Relation between the chemical structure and the rheological properties

“…When replacing PEO by PNIPA, the main idea was to use the wide chemistry of poly(N-substituted acrylamide) derivatives as well as their peculiar thermodynamic properties in water. In recent papers 10,11) we confirmed the basic principles established with PAA-g-PEO copolymers with PNIPA grafts and extended the rheological studies to a wide range of added co-solutes like salts, neutral molecules and surfactants. When we started the present work the original idea was to correlate the macroscopic properties with the primary structure of the copolymers.…”

“…The experimental procedure has already been described elsewhere 10,11) . Briefly, the grafting reaction was carried out in NMP at 60 8C where the required amounts of PAA, PNIPA and DCCI (coupling agent) were introduced successively.…”

“…In a previous paper we have reported the synthesis of graft copolymers combining a poly(sodium acrylate) (PAA) backbone and PNIPA side chains 10) . They were prepared according to a two-step procedure with 1) the synthesis of amino-terminated oligomers by telomerisation and 2) the grafting of the functional oligomers onto a poly(acrylic acid) precursor.…”

“…More recently we moved to other thermosensitive side chains based on poly(N-isopropylacrylamide), PNIPA, derivatives 10) . When replacing PEO by PNIPA, the main idea was to use the wide chemistry of poly(N-substituted acrylamide) derivatives as well as their peculiar thermodynamic properties in water.…”

Solution Properties of Hydrophobically-Modified Copolymers of N-Isopropylacrylamide and N-L-Valine Acrylamide. A Study by Fluorescence Spectroscopy and Microcalorimetry

“…We investigated the response of PNIPAM-Val-C18Py in aqueous media to changes in pH by recording the emission ofpyrene from solutions of PNIPAM-Val-C 18 Py in a series of citric acid buffers ranging in pH from 2 to 10. All solutions were of constant ionic strength (0.1 M NaCl) and the measurements were carried out at constant temperature, 15°C, a value selected such that it lies below the phase transition temperature of even the most acidic solution.…”