Open Conference Systems, StatPhys 27 Main Conference

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Multiscale Wrinkling Patterns in Helicoidal Plywood Surfaces
Alejandro Daniel Rey, Ziheng Wang

##manager.scheduler.building##: Edificio San Alberto Magno
##manager.scheduler.room##: Auditorio Santa Cecilia
Date: 2019-07-11 05:00 PM – 05:15 PM
Last modified: 2019-07-03

Abstract


Helicoidal plywoods are an ubiquitous biological fibrous composites structure found in collagen and cellulosic materials. These cholesteric liquid crystal analogues display the Bouligand architecture which is associated with bulk and surface multifunctionalities such as sensor/actuator and structural color , as well as optimized mechanical and tribological properties.    In this presentation, motivated and guided by biological surface topographies found in insects, plants, and fish scales, we present a model of surface pattern formation for chiral surfaces and reveal the elastic mechanisms that generate simple and complex wrinkling. Introducing the liquid crystal capillary vector we are able to efficiently map the relations between surface curvature, liquid crystal anchoring, chirality  and surface tension. Scaling laws of wrinkling amplitude and wave-length as a function of anchoring and chirality are derived. In the simplest case, a fiber orientation surface gradients generate a single scale harmonic whose amplitude is proportional to anchoring and whose wave-length is set by the orientation. We show how by manipulating the material property and fiber gradient space generates targeted patterns with desirable novel properties, such as low friction surfaces.