Assembly of large-area, highly ordered, crack-free inverse opal films
Birgit Hausmann
Reference
Keywords
Coassembly, colloidal assembly, crack-free films, inverse opals, nanoporous
Overview
A new synthesis of crack-free inverse opal films over cm length scales is presented. The two step process consists of a) an evaporative deposition of polymeric colloids in a hydrolyzed silicate sol-gel precursor solution and b) a colloidal/matrix coassembly. The preferential grwoth direction is <110>. The synthesis of multilayered hierarchical films are also demonstrated. Furthermore, the inverse opal films were converted to inverse opal films of other materials as porous Si and <math>TiO_2</math> while maintaining their morphology during the gas/solid displacement reaction.
Results and Discussion
Herein we demonstrate the evaporative coassembly of a sacrificial colloidal template with a matrix material in a single step to yield a colloidal composite, thereby avoiding the need for liquid infiltration into a preassembled porous structure
Cracking seems to occur along {111} planes for thin films, which is consistent with conventional evaporative deposited films, whereas thicker films seem to crack along {110} planes.
