R. Huang Group Research

S.-K. Ryu, Q. Zhao, M. Hecker, H. Y. Son, K. Y. Byun, J. Im, P.S. Ho, and R. Huang, Micro-Raman Spectroscopy and Analysis of Near-Surface Stresses in Silicon around Through-Silicon Vias for Three-Dimensional Interconnects. J. Appl. Phys. 111, 063513 (2012). 

This chapter summarizes our works on surface wrinkling of elastic thin films, taking a kinetics approach as a physical pathway to both ordered and disordered wrinkle patterns.

This paper has been accepted for publication in Soft Matter. DOI: 10.1039/c0sm00335b.

In a previous work, substrate-modulated morphology of graphene was analyzed using a numerical Monte Carlo method. Here we present an analytical approach that explicitly relates the van der Waals interaction energy to the surface corrugation and the interfacial properties. Moreover, the effect of mismatch strain is considered, which predicts a strain-induced instability under a compressive strain and reduced corrugation under a tensile strain.

A previous work suggested a critical condition to form surface creases in elastomers and gels. For elastomers, the critical condition seems to have closed a gap between experimental observations (e.g., by bending a rubber block) and the classical instability analysis by Biot. For gels, however, experiments have observed a wide range of critical swelling ratios, from around 2 to 3.7. Here we present a linear perturbation analysis for swollen hydrogels confined on a rigid substrate, which predicts critical swelling ratios in a similar range.

Q. Lu and R. Huang, Excess energy and deformation along free edges of graphene nanoribbons. Posted online at arXiv:0910.0912, October 2009.

Inspired by recent works by Wei Hong , Xuanhe Zhao, Zhigang Suo, and their coworkers, we started a project on hydrogels, with particular interest in various instability patterns observed in experiments. The attachment is our first manuscript on this subject. Through this work we hope to achieve the following: