Macromolecular engineering of nanostructured polymer film surfaces

The macromolecular engineering of polymer film surfaces via the design and synthesis of different polymer platforms enables tailoring the properties of nanostructured materials in a variety of high-tech applications. We focused on two different areas of current interest for innovation and advancement. The integration of conventional top-down approaches with the bottom-up self-assembly allows diblock copolymer films to be employed as precisely registered organic templates in nanolithography. In order to satisfy the requirements of the industrial nanofabrication technology, efforts are devoted to scaling down the dimension of the diblock copolymer lattice parameters. However, diblock copolymer materials have a limitation of their self-assembly properties depending on the product between the Flory-Huggins parameter χ and molecular weight N. Conventional lithographic materials, like polystyrene-b-polymethylmethacrylate (PS-b-PMMA), show a low χ which limits their application at sub-10 nm scale, and therefore new high-χ materials have to be synthesized. In this work a series of fluorinated PS-b-P(MMA-co-AF6) block copolymers were synthesized via ATRP with a gradient increment of 2-(perfluorohexyl)ethyl acrylate (AF6) units. The self-assembly these fluorinated diblock copolymers were studied by using a Rapid Thermal Processing (RTP) method both on flat silicon wafers and inside SiO2 periodical trenches. A comparison between these high-χ materials and the conventional ones is useful to understand how tailoring the synthesis of fluorinated diblock copolimer can help to overcome the imposed energetic limitation. Marine biofouling represents a big economic issue for marine industry. It limits performance of devices and materials, it increases costs related to maintenance and corrosion and it effects environmental pollution. In order to minimize this issue, the main current strategy is the use of biocidal coatings. In recent years research has been devoted to find non-toxic alternative strategies. Fouling-release coatings do not contain biocidal agents but facilitate removal of fouling organisms owing to their nanostructured and amphiphilic, ie ambigous, surface structure. In this framework, new amphiphilic polymer films were developed in order to create a film with an ambiguous surface. A di-hydroxy terminated polydimethylsiloxane was reacted with, alternatively or both mixed, an hydrophilic polyethylenoxysilane Si-PEG or an hydrophobic/lipophobic perfluorohexylsilane Si-F. These films were crosslinked by polycondensation curing. The films were subjected to ecotoxicological tests, using Vibro fischeri and Dunaliella tertiolecta, and tested with biological assays, using Ficopomatus enigmaticus and Navicula incerta as model fouling organisms.