Study And Fabrication Of Super-Repellent Porous Material

Bioinspired super-repellent materials are promising and potent in both industry and daily life. Super-repellency of materials relates to the chemical property and physical property of material surface. Among them, physical topography is the dispensable condition for achieving the super-repellency. Porous materials which are easy to fabricate, excellent in design and with large specific surface area can make full use of the porous structure. Porous materials thus gain excellent properties. However, it remains a hot but difficult issue to study and fabricate porous materials with excellent super-repellency.Herein, we analyzed and studied the connection between structure features and super-repellency of porous materials. And then different porous structures for highly transparent superhydrophobic coatings and microscale porous superamphiphobic coatings and matierlas were fabricated. The relationship between surface morphology, transparency and superhydrophobicity were studied. An ideal model was proposed. Thereafter, a wipe-coating method was developed to spontaneously acquire the ideal model and fabricate highly transparent and superhydrophobic coating. The correlation between structure features and superamphiphobicity of porous materials were studied. Afterwards, the most super-repellent porous material was successfully fabricated.(1) Based on spin-coating method and layer-by-layer assembly, the transparency and superhydrophobicity of the surfaces with heterogeneous nanoparticle assembled structures were studied. Two systems, i.e., (1) SiO2 nanoparticles accompanied with NH2-terminated silicone (SN2) or silicone modified prePU (SN2-prePU), (2) SiO2 nanoparticles accompanied with organo silica sol, have been utilized to study the structure, superhydrophobicity and transparency of the coatings with different compositions and layers. In the first system, SN2 was found to favor the transparency and superhydrophobicity of the coatings, meanwhile SN2-prePU favored the durability of the coating. In the second system, coatings prepared with higher concentration of organo silica sol/SiO2 nanoparticle dispersion were easily to be rendered with superhydrophobicity. On the contrary, coatings coated with lower concentration of organo silica sol/SiO2 nanoparticle dispersion displayed better transparency. Through PCM and SEM, we found that heterogeneneous nanoparticle assembled structures could not form effective structures to achieve both high transparency and superhydrophobicity.(2) Afterwards, we focued on the bulk property and surface property which affected the light absorption, light reflection and light scattering. Thereafter, an ideal structure named "silica nanoparticle assembled nanoscale porous structure (SNANPS)" was proposed to simultaneously acquire both high transparency and superhydrophobicity. By utilizing branched silica nanoparticles, the SNANPS could be formed spontaneously. Coatings based on the SNANPS were not only highly transparent and superhydrophobic, but also water impinging resistant, long-time water repellent, renewable and temperature stable. A wipe-coating method was developed and enabled us to fabricate the coatings onto almost all planar, patterned, curved and inner/outter surfaces of solid materials.(3) Taking dopamine and SiO2 nanoparticles as building blocks, dopamine/SiO2 nanoparticle assembled microscale porous structure was constructed through ice templation. Superamphiphobic coating was acquired based on the structure. Three porous coatings with different porous structure features and thus different super-repellency were studied. We found out that only with comparatively large pore size and pore height could the porous coating exhibit superamphiphobicity. Because dopamine was a kind of powerful adhesive, we were able to fabricate the coatings onto almost all solid materials.(4) Further, several porous materials with different structures and resulting different super-repellency have been studied to conclude the effects of porous structure features on the super-repellency. Criteria focusing on pore size, pore height, porous structure network thickness and secondary microscopic structure have been proposed. Based on the criteria, we have fabricated the most super-repellent superamphiphobic porous material thus far.