Dendritic-to-faceted crystal pattern transition of ultrathin poly(ethylene oxide) films.
The detailed T(c)-sensitive crystal pattern transition from dendrites through fourfold-symmetric structures to faceted crystals of ultrathin poly(ethylene oxide) films has been experimentally observed using atomic force microscopy. The transition has been quantitatively described by the T(c)-dependences of the fractal dimension and of the velocity ratio caused by forward and transverse growths in crystal tips. The essential aspect of the pattern selection and transition is mainly the competition of two macroscopic mechanisms: Nucleation-limited and diffusion-limited growths which create faceted and dendritic crystal patterns, respectively. Their combination is a facet growth within a diffusion field which will create a faceted dendrite.
Zhang
Guoliang
G
The Key Laboratory of Functional Polymer Materials of Ministry of Education and Institute of Polymer Chemistry, College of Chemistry, Nankai University, Tianjin 300071, China. guoliang2008@mail.nankai.edu.cn
Jin
Liuxin
L
Ma
Zhenpeng
Z
Zhai
Xuemei
X
Yang
Miao
M
Zheng
Ping
P
Wang
Wei
W
Wegner
Gerhard
G