Forces that drive nanoscale self-assembly on solid surfaces

2019-11-04 23:03:28

phase energy self assembly dependent

责任者: Suo, Z.;Lu, W. 单位: Dept. of Mech. & Aerosp. Eng., Princeton Univ., NJ, USA 来源出处: Journal of Nanoparticle Research(J. Nanoparticle Res. (Netherlands)),2000/12/,2(4):333-44 摘要: Experimental evidence has accumulated in the recent decade that nanoscale patterns can self-assemble on solid surfaces. A two-component monolayer grown on a solid surface may separate into distinct phases. Sometimes the phases select sizes of about 10 nm, and order into an array of stripes or disks. This paper reviews a model that accounts for this behavior. Attention is focused on thermodynamic forces that drive the self-assembly. A double-welled, composition-dependent free energy drives phase separation. The phase boundary energy drives phase coarsening. The concentration-dependent surface stress drives phase refinement. It is the competition between coarsening and refining that leads to size selection and spatial ordering. These thermodynamic forces are embodied in a nonlinear diffusion equation. Numerical simulations reveal rich dynamics of the pattern formation process. Phase separation and uniform size selection are relatively fast, but ordering over a long distance is exceedingly slow unless the symmetry is suitably broken 关键词: free energy;monolayers;nanostructured materials;phase separation;self-assembly;surface phase transformations;nanoscale self-assembly;solid surfaces;two-component monolayer;stripe array;disk array;thermodynamic forces;double-welled composition-dependent free energy;phase separation;phase boundary energy;phase coarsening;concentration-dependent surface stress;phase refinement;size selection;spatial ordering;nonlinear diffusion equation;numerical simulation;dynamics;pattern formation process;symmetry breaking