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Science in China Series B: Chemistry

, Volume 43, Issue 4, pp 428–434 | Cite as

Thermal reversible gelation during phase separation of poly(N-isopropyl acrylamide)/water solution

  • Fang Zeng
  • Xinxing Liu
  • Zhen Tong
  • Yanyin Yang
  • Shuizhu Wu
Article

Abstract

By dynamic viscoelastic measurement for PNIPAM/water solution it has been found that below the phase separation temperature (about 32°C), the system is homogeneous fluid; while upon being heated to about 32°C, the solution undergoes phase separation and the storage modulus G’ increases sharply and exceeds the loss modulus G”, indicating the physical network formation during the phase separation. Based on the percolation model, the gel points Tgel were obtained by applying the dynamic scaling theory (DST) and Winter’s criterion. The critical exponent n was also obtained to be 0.79 through DST, which is different from 0.67, the critical point of chemically crosslinked network predicted through DST. The obtained n value reflects the special property of physical network being different from chemical network.

Keywords

poly(N-isopropyl acrylamide) physical crosslink network thermal reversible gel 

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Copyright information

© Science in China Press 2000

Authors and Affiliations

  • Fang Zeng
    • 1
  • Xinxing Liu
    • 1
  • Zhen Tong
    • 1
  • Yanyin Yang
    • 1
  • Shuizhu Wu
    • 1
  1. 1.Institute of Materials ScienceSouth China University of TechnologyGuangzhouChina

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