Microcapsules have attracted much attention as a drug career. In the current study, we have prepared biodegradable poly (lactide-co-glycolide) (PLGA) microcapsules via the deposition of PLGA on W/O emulsion droplets. A combination of scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM) demonstrates the formation of PLGA microcapsules with a diameter of 5∼10 μm. The formation mechanism of PLGA microcapsules is proposed on the basis of the experimental results.
Porous and crystalline TiO2 films were prepared on individual metallic Ti plates by the micro-arc oxidation (MAO) method. A novel dye-sensitized solar cell (DSSC) was fabricated ; a TiO2 film prepared on a metallic Ti plate was used as the cathode, and an indium tin oxide (ITO) glass plate was employed as the anode. This cell possessed characteristics of DSSC. The TiO2 films were prepared in NH4H2PO4, (NH4)2HPO4, and (NH4)3PO4 electrolyte solutions by MAO. Their crystal structures were characterized by an X-ray diffractometer (XRD), surface morphologies were observed by a scanning electron microscope (SEM), and thicknesses were measured using an eddy-current-type film thickness meter. The results indicated that all films comprised a single-phase of anatase TiO2, exhibited porous surfaces, and had thicknesses in the range of about 2∼5 μm. The effects of the electrolyte solutions on the TiO2 films prepared in them were evaluated. It was found that the TiO2 film prepared in (NH4)2HPO4 exhibited the smallest pore size, namely, 0.5 μm and the smoothest surface morphology. The maximum starting power of a DSSC fabricated in this study was 394.7 mV.
This review focuses on pH-responsive diblock copolymers as stimulus responsive amphiphilic materials : (i) adsorption characteristics of pH-responsive diblock copolymers at the mica/aqueous solution and silica/aqueous solution interfaces ; (ii) pH-responsive behavior of the copolymer films adsorbed at the solid/aqueous solution interfaces and (iii) development of micellar multilayers based on the Layer-by-Layer deposition.
Small-angle X-ray scattering (SAXS) is a well-established technique, which plays an important role in structural characterization on a length scale of ca. 1∼100 nm. Since many physical properties of nano-materials are often closely linked with size, shape, and internal structure of their components, and interaction potentials, precise and rapid structural characterization is expected to be more and more desired. After brief introduction into theoretical aspects of scattering methods, our recent SAXS experiments on lyotropic liquid crystals, micellar solutions, protein solutions, and vesicle dispersions are presented, aiming at intuitively showing ‘what can be learnt from SAXS’ to scientists and engineers working on diverse material sciences as well as surfactant chemistry.
Heterogemini surfactants with nonidentical headgroups such as ammonium and carboxylate (cationic - anionic), ammonium and gluconamide (cationic - nonionic), and ammonium and sulfobetaine (cationic - zwitterionic) were designed and synthesized, and their surface properties and aggregation behavior in aqueous solution were investigated. It was shown that they have high surface activities and unique aggregation behavior in comparison with the corresponding monomeric surfactants, gemini surfactants with the identical headgroups, and mixed monomeric surfactants.
Surfactants having a fluorocarbon chain and a hydrocarbon chain in the molecule, namely, hybrid surfactants, have been developed recently, and their syntheses procedure and solution properties have been discussed. Hybrid surfactants are a new class of surfactants exhibiting unique properties that are not exhibited by conventional hydrocarbon surfactants.