Takamichi Shinohara

Preparation of poly(lactic-acid)-particle stabilized liquid marble and the improvement of its stability by uniform shell formation through solvent vapor exposure

A liquid marble was prepared from bio-based poly(lactic acid) [PLA] microparticles and water droplets. Solvent vapor exposure to the liquid marble changed the morphology of the granular PLA microparticle shell layer to a film-like shell layer even though the spherical shape of the liquid marble is retained. The morphological changes suppressed the evaporation of the water within the liquid marble by a factor of six compared with a liquid marble without the solvent vapor treatment. The compression test revealed that the mechanical stability of the solvent-treated liquid marble was changed due to the increased rigidity of the shell structure. Solvent vapor exposure is a simple but effective way to fabricate a robust liquid marble with long-term stability.

Characterization of Surface Microstructures on Bio-based Polymer Film Fabricated with Nano-imprint Lithography by Synchrotron Radiation Small Angle X-ray Scattering

Nano-imprint lithography (NIL) is a simple, low cost and high-resolution patterning method. However the precise evaluation method of nano-imprinted structure has not been established. Synchrotron radiation small angle X-ray scattering (SR-SAXS) measurement is a nondestructive and high resolution characterization method. In this study, we attempt to fabricate nanostructures on the poly(lactic acid) (PLA) film by NIL and evaluated with microscopic and scattering techniques. The mold with line/space pattern was used for NIL. Scanning electron microscope observation confirmed the formation of surface nano-structure in large areas. Also, nano-imprinted PLA film was evaluated using SR-SAXS measurement. The scattering patterns obtained from nano-imprinted PLA films were clearly observed up to higher order scattering spots. These results suggested that highly regular structure was fabricated on the surface of PLA films.

Grazing-incidence wide-angle X-ray diffraction study on molecular aggregation state of imprinted polyimide film before and after hard baking

Nanoimprint lithography (NIL) was carried out on precursor of polyimide (PI), poly(amic acid) film, and then hard baking to obtain imprinted PI film. The molecular aggregation states of imprinted PI films before and after hard baking were investigated by grazing-incidence wide-angle X-ray diffraction comparing with the one of flat PI film. It was found that NIL and hard baking can strongly affect the molecular aggregation states of PI film. Before hard baking, PI chain is aligned parallel to the line direction on the line. After hard baking, the alignment in ordered domain was changed to that the PI molecule of which chain axis is perpendicular to the line direction is significantly increased, while, PI molecule of which chain axis is parallel to the line direction is decreased after hard baking. Through comparing with the flat PI, crystallinity of imprinted PI film has been significantly enhanced.