Oblique wrinkling patterns on liquid crystal polymer core-shell cylinders under thermal load

INTERNATIONAL JOURNAL OF SOLIDS AND STRUCTURES

卷:208

Article

Zhao, Shichen¹  Xu, Fan¹  Fu, Chenbo¹  Huo, Yongzhong¹ 

[1] Fudan Univ, Inst Mech & Computat Engn, Dept Aeronaut & Astronaut, 220 Handan Rd, Shanghai 200433, Peoples R China

关键词: Anisotropic spontaneous strain;    LCP film/substrate;    Director orientation;    Thermal wrinkling;    Pattern formation;   

DOI  :  10.1016/j.ijsolstr.2020.11.005

来源: Elsevier

【 摘 要 】

Smart soft materials, which can flexibly respond to external multi-physics stimuli, have attracted considerable attention over the past few years. Here, we present tunable wrinkling patterns in cylindrical core-shell systems under thermal load via the orientation of director in nematic liquid crystal polymer (LCP). To quantitatively analyze mechanical behavior and morphological evolution of LCP core-shell cylinders, we develop a core-shell model that accounts for director-induced anisotropic spontaneous strains. By tuning the alignment of liquid crystal director, we explore the effects of anisotropy of spontaneous strains on instability pattern formation and evolution. When the director is along the circumferential direction, wrinkling pattern can be axisymmetric or diamond-like, determined by a single dimensionless parameter C-s which characterizes the stiffness ratio and curvature of the system. When the director is parallel to the axial direction, leading to circumferential expansion upon heating, the core-shell cylinder usually buckles into churro-like mode. For general spatial director alignment, the ultimate wrinkling patterns depending on the anisotropy state of spontaneous strains, can be diamond-like, parallel bead-chain or oblique stripe mode. We draw director-affected phase diagrams to provide an overall view of pattern selection affected by liquid crystal director orientation, which could be used to quantitatively guide the effective design of wrinkling morphology-related smart surfaces. (C) 2020 Elsevier Ltd. All rights reserved.

【 授权许可】

Free