Fabrication of Patterned Superhydrophobic Polybenzoxazine Hybrid Surfaces

Abstract

The hydrophilicity of bis(3-allyl-3,4-dihydro-2H-1,3-benzoxazinyl)isopropane(B-ala) polybenzoxazine film and superhydrophobic polybenzoxazine-hybrid surface can be controlled through UV exposure to change the ratio of intra- to intermolecular hydrogen bonds. A fraction of the intramolecular hydrogen bonding of the as-cured sample will convert into intermolecular hydrogen bonding upon UV exposure and thus results in an increase of hydrophilicity. This simple method allows for manipulating the hydrophilicity at selected regions on a superhydrophobic polybenzoxazine hybrid surface to create a patterned surface with superhydrophobic and superhydrophilic regions. Additionally, we have found that the superhydrophobic polybenzoxazine-silica hybrid surface exhibits good adhesion of water droplets after UV exposure, which can be served as a "mechanical hand" to transfer water droplets from a superhydrophobic surface to a hydrophilic one.

Preparation of superhydrophobic cauliflower-like silica nanospheres with tunable water adhesion

“…A hypothesis was made that the surface composition was identical to the average composition of the particles, so the surface SiOH group percentages of all Si atoms (SiOH content) can be directly derived from the 29 Si MAS NMR analysis as reported. [43][44][45] In the 29 Si MAS NMR spectra, Q signals, resulting from the hydrolysis and condensation of the TEOS silicon precursor, correspond to silicon atoms directly bonded to other silicon atoms by oxygen bridges.…”

“…[43][44][45] In the 29 Si MAS NMR spectra, Q signals, resulting from the hydrolysis and condensation of the TEOS silicon precursor, correspond to silicon atoms directly bonded to other silicon atoms by oxygen bridges. T signals correspond to silicon atoms directly bonded to carbon atoms coming from the incorporation of organosilicon precursors.…”

“…T signals correspond to silicon atoms directly bonded to carbon atoms coming from the incorporation of organosilicon precursors. Since the 29 Si NMR analysis have been carried out using a single pulse, the results are quantitative. Thus, the areas below the Gaussian curves obtained from the deconvolutions of the spectra are proportional to the abundance of each species.…”

“…Although this sticky surface is not self-cleaning, it can provide some fascinating applications in manipulating liquids at the micrometre scale. 29,30 Jiang's group initially fabricated a superhydrophobic surface with high adhesive force, which was composed of aligned polystyrene nanotubes. 30 Since then, different progress has been made.…”

“…30 Since then, different progress has been made. 25,26,29,[31][32][33][34][35] A nano-patterned surface is usually essential to assure the superhydrophobicity, and adhesive force was produced by either the water droplet penetrating into the porous structure or the capillary force between the water droplet and the surface. Up to now, successful control of the water adhesion with a convenient procedure is very lacking.…”