title: Dendritic-to-faceted crystal pattern transition of ultrathin poly(ethylene oxide) films.
abstract: 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.
authors.affiliation: 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
authors.forename: Guoliang
authors.initials: G
authors.lastname: Zhang
authors.forename: Liuxin
authors.initials: L
authors.lastname: Jin
authors.forename: Zhenpeng
authors.initials: Z
authors.lastname: Ma
authors.forename: Xuemei
authors.initials: X
authors.lastname: Zhai
authors.forename: Miao
authors.initials: M
authors.lastname: Yang
authors.forename: Ping
authors.initials: P
authors.lastname: Zheng
authors.forename: Wei
authors.initials: W
authors.lastname: Wang
authors.forename: Gerhard
authors.initials: G
authors.lastname: Wegner