Self-Association of a Thermosensitive Amphiphilic Block Copolymer Poly(N‑isopropylacrylamide)‑b‑poly(N‑vinyl-2-pyrrolidone) in Aqueous Solution upon Heating

Self-Association of a Thermosensitive Amphiphilic Block Copolymer Poly(N‑isopropylacrylamide)‑b‑poly(N‑vinyl-2-pyrrolidone) in Aqueous Solution upon Heating

The self-association behavior of a thermosensitive amphiphilic block copolymer, poly(N-isopropylacrylamide)-b-poly(N-vinyl-2-pyrrolidone) (PNIPAM-b-PNVP) in water upon heating was investigated by static and dynamic light scattering (SLS and DLS), small-angle X-ray scattering (SAXS), and pulsed field...

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Bibliographic Details
Published in:Macromolecules Vol. 46; no. 1; pp. 226 - 235
Main Authors: Sato, Takahiro, Tanaka, Kohei, Toyokura, Akiko, Mori, Rika, Takahashi, Rintaro, Terao, Ken, Yusa, Shin-ichi
Format: Journal Article
Language:English
Published: Washington, DC American Chemical Society 08-01-2013
Subjects:
Applied sciences
Exact sciences and technology
Organic polymers
Physicochemistry of polymers
Properties and characterization
Solution and gel properties
Temperature effect
Composition effect
Radius of gyration
Acrylamide derivative copolymer
Experimental study
Monodispersed polymer
Phase separation
Diblock copolymer
Pyrrolidone(vinyl) copolymer
Molecular aggregation
Aqueous solution
Micellization
Amphiphilic polymer
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Summary:The self-association behavior of a thermosensitive amphiphilic block copolymer, poly(N-isopropylacrylamide)-b-poly(N-vinyl-2-pyrrolidone) (PNIPAM-b-PNVP) in water upon heating was investigated by static and dynamic light scattering (SLS and DLS), small-angle X-ray scattering (SAXS), and pulsed field gradient NMR (PFG-NMR). Combining SLS and DLS with SAXS and PFG-NMR, we conclude that above 40 °C, the unimer or a few arms star micelle of the copolymer coexists with large spherical particles of uniform density, which should be regarded as concentrated-phase droplets produced by a liquid–liquid phase separation. The spherical particles of PNIPAM-b-PNVP samples with the PNIPAM content less than 0.32 became smaller with increasing temperature. This temperature dependence was explained in terms of the packing parameter for amphiphiles.
ISSN:0024-9297
1520-5835
DOI:10.1021/ma3020992