Research On The Preparation Of Metal-and Polymer-based Patterned Hierarchical Structures Via Breath Figure Method

Breath figure(BF)method is a cost-efficient and flexible surface patterning technique.Two types of hierarchical structures with hierarchy of different length scales were formed by the implementation of unconventional BF processes.Arrays of metallic nanoparticle(NP)assemblies with both micro-and nanoscale features and regionally patterned BF pore arrays with regular millimeter scale compartments were fabricated via the BF lithography and solvent-treatment BF(st-BF)method,respectively.A templated-self-assembly(TSA)procedure was employed to fabricate bi-metallic arrays with hierarchical structures made from Au and Pt NPs.Conventional BF procedure was performed to directly prepare the perforated BF films.The influences of different polymer solution concentrations and the added amount of surfactant on the formation of the perforated BF films were explored.Masked by the BF template,sputtering was used to deposit the Pt NPs into patterned discs,which were further used to induce the selective deposition of Au NPs obtained through in-situ synthesis.Ordered bi-metallic array with superstructure of Au micro-rings decorating the Pt discs were formed by following such TSA procedure of self-assembly processes.The formation of this unusual bi-metallic patterned array was attributed to the adsorption behavior of the PVP which served as protective agent for the deposited Au NPs.The bi-metallic sample with Au rings was proved to possess property of significant SERS enhancement upon the detection of4-aminothiophenol down to the low concentration of 10^-9 mol/L,as well as great reproducibility,with the relative standard deviation of the Raman intensity being as low as 3.3%.By templated replication,pre-patterned polymeric substrate with millimeter-scale feature was prepared.Such substrates made from polymethyl methacrylate(PMMA)and polylactic acid(PLA)were used to perform the st-BF method.For st-BF process,the polymeric objects were directly treated with organic solvents under the environmental conditions of finely controlled temperature and humidity,and the honeycomb-structured pore arrays could be facilely formed upon the upper surface of the treated object.For PMMA pre-patterned substrates,the influence of different solvents on the pore formation was investigated.For the PLA pre-patterned substrates,the influence of temperature,humidity and the added amount of surfactant on the pore formation was investigated.And the results show that the polymer-based hierarchical structures can be readily obtained.By manipulating the pore morphologies within different compartments of the pre-patterned substrate,functional hierarchical structures with gradient features could be established.