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.
Department of Polymer Science and Engineering, University of Science and Technology of China, Hefei, Anhui 230026, China.
Jian
J
Xu
Zhiyuan
Z
Zhu
Shizhong
S
Luo
Chi
C
Wu
Shiyong
S
Liu