Browsing by Subject "Hydrophobicity"

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    Morfología Fluvial.-El papel de la vegetación de pinar y de matorral en la regeneración de los suelos afectados por los incendios forestales. Efectos hidrológicos y erosivos en el año posterior al incendio
    Cerdá, A.; Bodí, M.B.; Doerr, S.H.; Mataix-Solera, J.; Universidad de Murcia
    ABSTRACT Forest fires provide an excellent opportunity to understand the relationship between vegetation and erosion. This is because changes in vegetation and erosion processes and rates are highly dynamics after the fire. Through simulated rainfall and WDPT (Water Drop Penetration Time) tests the soil water repellency and the runoff and erosion rates after a fire in the Serra Grossa Range, Eastern Spain, was measured. Sampling (six plots) was carried out in October 2002 and July 2003, under wet and dry conditions respectively. The results show high losses of soil and water during the October 2002 measurements for both vegetation covers: pine (Pinus halepensis) and scrubland (Ulex parviflorus y Cistus albidus). However, during the July 2003 measurements, the pine forest area continues to show high rates of erosion while the shrub is drastically reduced as the runoff was lower. This was due to the higher soil water repellency on the pine covered soils, what caused the increase in runoff and the acceleration of erosion processes. Therefore, the type of vegetation influences the erosive processes, which must be taken into account in forest policy.
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    Scratch-Resistant Hydrophobic Coating with Supramolecular-Polymer Co-Assembly
    (Wiley-VCH, 2023-10-06) Lee, Pin-Wei; Saura Sanmartín, Adrián; Schalley, Christoph A.; Química Orgánica
    Supramolecular assembly for superhydrophobic coatings is known for its efficiency and efficacy. However, the mechanical fragility of the coatings limits their use as coating materials. Herein, the combination of (±)-N,N'-(trans-cyclohexane-1,2-diyl)-bis(perfluorooctanamide) CF7, a cyclohexyl diamide-based low molecular weight gelator, with acrylate polymers for the generation of semi-transparent omniphobic coatings with significantly enhanced scratch proofness is presented. CF7 has shown the ability to self-assemble in common solvents into highly entangled fibrous networks with extreme water repellency. The incorporation of covalent polymers, specifically poly(methyl methacrylate) (PMMA) and poly(trifluoroethyl methacrylate) (PTFEMA), helps to fixate the supramolecular CF7 fibers without interfering with the self-assembled structures. The resulting coatings, namely CF7/PMMA and CF7/PTFEMA, show significantly improved mechanical resistance as well as optical transparency while maintaining excellent water and oil repellency. Furthermore, the homogeneity of the coating in bulk is confirmed by depth profiling of the 3D distribution of the components using time-of-flight secondary ion mass spectrometry imaging, which turns out to be an essential technique in order to characterize such materials.