Compressive Behaviors of Hydrophobic Sheets Using Finite Element Analysis

Abstract

Thai Microelectronics Centre (TMEC) used soft lithography techniques to fabricate hydrophobic sheets made of PDMS material for various micropillar patterns. The F8 and F13 micropatterns had high water contact angle and resisted high compressive load on top of hydrophobic sheets [17]. This research aimed to reinvestigate for truly understanding compressive behavior of these micropillar patterns under compressive loading. The finite element models of F8 and F13 micropatterns were constructed in Ansys APDL 2019R3 software. The accurate material model for PDMS under compressive loading was Ogden 3^rd parameter material model as discussed in [13]. We introduce a novel mathematical technique implemented in MATLAB R2021a software. This technique aims to ascertain material constants and their associated stability regions. While the proposed method for determining material constants is deemed innovative and intriguing. Finally, uniform compressive load as a function of vertical deformation was found for each micropillar pattern. We found that load-deflection curves were stiffer than previous study discussed in [17] since we had no strain limit range in our study. Finally, the maximum uniform compressive loads, before the initial collapse of micropillar patterns, were 34.334 kPa and 16.694 kPa for F8 and F13 micropatterns respectively.