Contraction and Collapsing Kinetics of Single Synthetic Polymer Chains at Small Quench Depths
✍ Scribed by Jinming Hu; Di Wang; Jian Xu; Zhiyuan Zhu; Shiyong Liu
- Publisher
- John Wiley and Sons
- Year
- 2010
- Tongue
- English
- Weight
- 869 KB
- Volume
- 211
- Category
- Article
- ISSN
- 1022-1352
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✦ Synopsis
Abstract
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. magnified image