Hierarchically Structured Multifunctional Porous Interfaces through Water Templated Self-Assembly of Ternary Systems

摘要

Herein, a facile water-assisted templatingnapproach, the so-called breath figures method, has beennemployed to prepare multifunctional and hierarchicallynstructured porous patterned films with order at differentnlength scales (nano- and micrometer). Tetrahydrofurannsolutions of ternary blends consisting on high molecularnweight polystyrene, an amphiphilic block copolymer, polystyrene-nb-poly[poly(ethylene glycol) methyl ether methacrylate]n(PS40-b-P(PEGMA300)48), and a fluorinated copolymer,npolystyrene-b-poly(2,3,4,5,6-pentafluorostyrene) (P5FS21-b-nPS31), have been used to obtain films varying the proportionnof the three components. Confocal micro-Raman spectroscopynand atomic force microscopy demonstrated the preferentialnlocation of the different functionalities in the films. Because of the breath figures mechanism, the amphiphilic copolymer yieldnpores enriched in hydrophilic functionality while the fluorinated copolymer remained mixed with the PS matrix and eventuallynalso forming self-assembled nanostructures at the surface. As a consequence, two levels of order can be observed, i.e., micrometernsize pores with nanostructured domains due to the block copolymer self-assembly. In addition, the distribution of the amphiphilicncopolymer within the holes is not regular being located principally on the edges of the cavities. This can be attributed to thencoffee stain phenomenon occurring in the water droplets as a consequence of the segregation of the block copolymers to thendroplets and their self-assembly.