Substrate suppression of thermal roughness in stacked supported bilayers


Curt M. De Caro, Justin D. Berry, Laurence B. Lurio, Yicong Ma, Gang Chen, Sunil Sinha, Lobat Tayebi, Atul N. Parikh, Zhang Jiang, and Alec R. Sandy, Physical Review E 84, 041914 2011

We have fabricated a stack of five 1,2-dipalmitoyl-sn-3-phosphatidylethanolamine (DPPE) bilayers supported on a polished silicon substrate in excess water. The density profile of these stacks normal to the substrate was obtained through analysis of x-ray reflectivity. Near the substrate, we find the layer roughness and repeat spacing are both significantly smaller than values found in bulk multilayer systems. The reduced spacing and roughness result from suppression of lateral fluctuations due to the flat substrate boundary. The layer spacing decrease then occurs due to reduced Helfrich repulsion.

DOI: 10.1103/PhysRevE.84.041914