The monodisperse silica particles self-assembled colloidal crystals were used as templates to synthesize pH value and temperature responsive ordered macorporous hydrogels. The ordered structure arranged by the uniform pores and the pore-pore interconnectivity through the window channel is confirmed by SEM characterization. UV-Vis-near IR absorption experiment result reveals that the wavelength at the stop band peak is tunable within the whole visible spectrum via simply altering some parameters such as pH value and light incidence angle. This finding allows to design frequency-tunable photonic band gap materials.
Monodisperse core-shell (polystyrene/DAAM-EA-AM) emulsions were prepared by two-step seed polymerization,and crosslinked films were obtained by ambient drying the copolymerization emulsions accompanying a interfacial crosslinking between DAAM/ADDH.The crosslinking degree increased with thermal treatment temperature and time.After alkaline hydrolysis of ester and amide groups resulting carboxylic groups,the films were transformed to be mesostructured hydrogels.The chemical composition and ordered morphologies were experimentally confirmed by FT-IR,SEM and POM.Water uptake of the hydrogels decreased with the thermal treatment time of the films,implying the crosslinking degree also increased.
Wettability is a fundamental property of solids surface, which is governed by both their chemistry and surface morphology. Titania is an interesting semiconductor, whose surface can display supra-amphiphilicity after being irradiated by UV light. This property leads to many attractive potential applications. Howerer, this property gradually loses upon the cessation of the irradiation. It is urgently required to fabricate a titania surface with amphiphilic property, independent on UV light irradiation. Herein, we propose to achieve an amphiphilic titania coating with macropores by dip-coating titania/polymer capsule dispersion followed by the removal of the polymer cores. The porous coating is permanently amphiphilic independent on UV irradiation, which is significantly different from the bulk ones. The amphiphilicity of the porous coating is greatly enhanced up to supra-amphiphilicity by a proper dose of UV irradiation similar to the thin film. Since the size is less than 100 nm, visible light scattering is avoided and the porous coating is transparent. Anatase titania coating with the pores retained is achieved after being calcined at 450 ℃, meanwhile adhesion of the coating on the substrates becomes stronger. The features of the porous coating facilitate its potential applications.
A new method was proposed to prepare binary composite colloidal crystal hydrogels by interlocking the as-prepared polystyrene/sulfonated polystyrene core/shell colloidal crystal hydrogel with a second responsive gel.The shell thickness thus the core size were synchronously controlled by altering the sulfonation time and temperature.The proper monomers were radically polymerized forming the second gel within the first gel network.The composition and structure were confirmed.Nanopatterned hydrogel including porous bulk hydrogels and surface patterned hydrogels were derived by properly treating the binary composite hydrogels.Specially,some typical patterns such as arrays of “nano-bowls",arrays of “nano-ribbons" and “nano-mask" were achieved by changing the treatment method such as by immersion in the solvent,after solvent evaporation from the sample surface during high rate rotation.This work provides a method to prepare nanopatterned hydrogels.
