First observation of two-stage collapsing kinetics of a single synthetic polymer chain.
Using a narrowly distributed poly(N-isoporpylacrylamide) (PNIPAM) chain with a degree of polymerization (N) of 3100, randomly labeled with pyrene, we have, for the first time, observed the two-stage kinetics of the coil-to-globule transition. Two characteristic relaxation times, tau(fast) for the crumpling of a random coil (approximately 12 ms) and tau(slow) for the collapsing of the crumpled chain to a compact globule (approximately 270 ms), were measured. To our knowledge, this is the first experimental evidence supporting the two-stage collapsing kinetics of single synthetic polymer chain previously proposed by de Gennes, Dawson, and Grosberg.
Xu
Jian
J
Department of Polymer Science and Engineering, University of Science and Technology of China, Hefei, Anhui 230026, China.
Zhu
Zhiyuan
Z
Luo
Shizhong
S
Wu
Chi
C
Liu
Shiyong
S