Title: Physically programmable surfaces
Description: The progress of civilization has depended on the development of materials whose properties can be increasingly finely customized. Such customization reached an apotheosis with the availability of materials that could support readily-programmed universal computation. With the software revolution arguably complete, it is natural to look to the physical world of atoms not yet sequestered for computation for the next great leaps in material control. To bring the benefits of software to matter, novel properties and forms of programmability must be developed. The natural place to begin with adding functionality to materials is at their surfaces, where they are likeliest to interact with the world. In this thesis, I demonstrate novel functionality relating to six physical characteristics of surfaces: chemical, electrical, thermal, hydrodynamic, mechanical, and magnetic properties. For chemical programmability, I show how gaps between electrodes with precisely controllable widths can be synthesized, enabling chemical specificity. For electrical programmability, I show that nanowire interconnects can be assembled, reconfigured, and disassembled on a surface. For thermal programmability, I show that by varying the surface chemistry of diamond films, different thicknesses of ice films can be stabilized at elevated temperatures. For hydrodynamic programmability, I show that hollow semiconductor nanostructures of various geometries can be synthesized, allowing sub-attoliter liquid transport on surfaces. For mechanical programmability, I show how a large particle can be stochastically manipulated through tossing by a vibrated bed of smaller particles. For magnetic programmability, I show that ensembles of local Ising-like interactions on 1-D and 2-D lattices lead to rich pattern formation that can partially be predicted.