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Composite fiber mats of a fluorinated acrylic copolymer and hydrophobic fumed silicon dioxide nanoparticles were produced through electrospinning process from a single solution. Morphological and chemical analysis of the fibers revealed that the nanoparticles were well-dispersed throughout the polymer matrix. Nanofiber mats showed much higher hydrophobicity and oleophobicity than sprayed surfaces of the same material, with contact angles above 150° for water as well as lower surface tension organic liquids and oils. Moreover, layers of fibers were observed to peel away with rolling droplets while preserving the morphology of the underlying layers. Based on the dynamics of rolling droplets on the nanofiber mats as they were being encapsulated, a simple model to estimate the force needed to peel away fibers was created. This “peel-away” surface can offer a new approach to the preservation of omni-phobicity upon wear damage. [ABSTRACT FROM AUTHOR]

Aleuritic (9,10,16-trihydroxypalmitic) acid self-assembly on mica from solution has been studied using AFM, ATR-FTIR and MD simulations. The goal of this study is to define the role of hydroxyl groups in the interaction between molecules as reference data to understand the mechanism of formation of synthetic and natural biopolyesters from polyhydroxylated long chain carboxylic acids. In a confined structure, such as the one imposed by a vertically self-assembled layer on mica, aleuritic acid has a tendency to adopt a monolayer configuration ruled by the lateral interactions between molecules viathe two secondary hydroxyl groups. This (2D) growth competes with the multilayer formation (3D), which is conditioned by the terminal primary hydroxyl group. As the self-assembly spatial constraint is relaxed, MD has shown that the structure tends to become an amorphous and crosslinked phase that can be characterized by topographic and friction force AFM data. [ABSTRACT FROM AUTHOR]