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Contraction and Collapsing Kinetics of Single Synthetic Polymer Chains at Small Quench Depths
Author(s) -
Hu Jinming,
Wang Di,
Xu Jian,
Zhu Zhiyuan,
Liu Shiyong
Publication year - 2010
Publication title -
macromolecular chemistry and physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.57
H-Index - 112
eISSN - 1521-3935
pISSN - 1022-1352
DOI - 10.1002/macp.201000476
Subject(s) - kinetics , isotropy , polymer , millisecond , chemistry , solvent , scattering , pyrene , relaxation (psychology) , physics , polymer chemistry , crystallography , materials science , nuclear magnetic resonance , optics , organic chemistry , quantum mechanics , astronomy , psychology , social psychology
Chain contraction and collapsing kinetics of pyrene‐labeled poly( N ‐isopropylacrylamide) (PNIPAM) single chains ( $\overline {M} _{{\rm n}} $ = 3.64 × 10 5 g · mol −1 , $\overline {M} _{{\rm w}} /\overline {M} _{{\rm n}} $ = 1.17) were investigated by employing the stopped‐flow technique coupled with fluorescence and light scattering detections, which can achieve millisecond jumping of solvent quality from good to above and below the θ ‐solvent condition at small quench depths. It was found that the coil‐to‐crumpled globule transition proceeds via an isotropic one stage process and the obtained characteristic relaxation times exhibit a monotonic decrease with increasing quench depths. The obtained experimental results were in qualitative agreement with previous theoretical considerations.