Facile design of sticky near superamphiphobic surfaces on highly porous substrate

Several sticky near superamphiphobic surfaces were fabricated on naturally porous and rough substrate by simply deposing oligoamides solutions, needless of surface modification or integrating nano-materials. These surfaces exhibit very high water and oil contact angles (CA) (water CA > 150 degrees, oil CA > 140 degrees) together with high sliding angles (> 90 degrees). The nanomaterial-free coating compounds are well-defined, homologous partially fluorinated oligoamides (synthesized via condensation reactions) which have consistent but slightly varied properties, in terms of CA and CA hysteresis. These surfaces show very high adhesion force to water droplets; in essence, the strong adhesion force is owing to the combination of capillary force derived from newly generated micro-porosity of substrate and the interaction between amidic groups of coating and water molecules. Besides, they exhibit high stability and durability after water immersion test. This approach may provoke new ideas for creating superamphiphobic surfaces with special adhesion properties on porous substrates. Moreover, these materials could also be potentially employed as water repellents for porous building materials, since they are easy to handle and soluble in environmentally benign solvents. In addition to very high water inhibition efficiency, they manifest high residual vapor permeability and preserve the physical characteristics, i.e. vapor diffusivity and chromatic features, of substrate. (C) 2018 Elsevier Ltd. All rights reserved.