Paretkar Dadhichi, Xu Xuejuan, Hui Chung-Yuen, Jagota Anand
Department of Chemical Engineering, Lehigh University, Bethlehem, PA 18015, USA.
Soft Matter. 2014 Jun 21;10(23):4084-90. doi: 10.1039/c3sm52891j.
We measured the shape change of periodic ridge surface profiles in gelatin organogels resulting from deformation driven by their solid-vapor surface stress. A gelatin organogel was molded onto poly-dimethylsiloxane (PDMS) masters having ridge heights of 1.7 and 2.7 μm and several periodicities. Gel replicas were found to have a shape deformed significantly compared to their PDMS master. Systematically larger deformations in gels were measured for lower elastic moduli. Measuring the elastic modulus independently, we estimate a surface stress of 107 ± 7 mN m(-1) for the organogels in solvent composed of 70 wt% glycerol and 30 wt% water. Shape changes are in agreement with a small strain linear elastic theory. We also measured the deformation of deeper ridges (with height 13 μm), and analysed the resulting large surface strains using finite element analysis.
我们测量了明胶有机凝胶中周期性脊状表面轮廓因固-气表面应力驱动的变形而产生的形状变化。将明胶有机凝胶模制在具有1.7和2.7μm的脊高以及几种周期性的聚二甲基硅氧烷（PDMS）母模上。发现凝胶复制品与其PDMS母模相比具有明显变形的形状。对于较低的弹性模量，在凝胶中测量到系统地更大的变形。独立测量弹性模量后，我们估计在由70 wt%甘油和30 wt%水组成的溶剂中的有机凝胶的表面应力为107±7 mN m(-1)。形状变化与小应变线性弹性理论一致。我们还测量了更深脊（高度为13μm）的变形，并使用有限元分析分析了由此产生的大表面应变。
