Atsushi Shishido

The design of functional and stimuli-responsive materials is among the key goals of modern materials science.

Optical switching behavior of low-molecular-weight and polymer azobenzene liquid crystals (LCs) was explored by means of reflection-mode analysis. Reflectivity changed on pulse irradiation under various conditions of orientations of LC molecules with respect to incident probe light, either s-polarization or p-polarization. For the low-molecular-weight LCs, we obtained a response time of 100 μs, which was very similar to that observed in the transmission-mode analysis, while we observed a decay t

Hierarchical control of two-dimensional (2D) molecular alignment patterns over large areas is essential for designing high-functional organic materials and devices. However, even by the most powerful current methods, dye molecules that discolor and destabilize the materials need to be doped in, complicating the process. We present a dye-free alignment patterning technique, based on a scanning wave photopolymerization (SWaP) concept, that achieves a spatial light-triggered mass flow to direct mol

Photochemical phase transition behavior of photochromic azobenzene liquid crystals (LCs) was explored by means of reflection-mode analysis. On pulse irradiation at 355 nm, which causes trans−cis isomerization of the azobenzene moiety, these LCs underwent nematic (N) to isotropic (I) phase transition in 100 μs as probed by change in reflectivity at the interface between the sample and glass substrate. The N−I phase transition was confirmed by calculation of the refractive index of the sample befo

Two-dimensional (2D) titania arrays with periods of 0.8–2.0 μm were fabricated by polymerization of a photosensitive titanium-containing monomer film using interference photolithography. The 2D precursor arrays were prepared by exposing a mixture of methacrylic acid, ethyleneglycol dimethacrylate, and titanium ethoxide doped with photoinitiator to 355 nm, 15 ns pulses from a Nd-Yttrium–aluminum–garnet laser and then rinsing with methanol. Pure titania arrays were obtained from the precursor arra

It is demonstrated that halogen bonding can be used to construct low-molecular-weight supramolecular complexes with unique light-responsive properties. In particular, halogen bonding drives the formation of a photoresponsive liquid-crystalline complex between a non-mesogenic halogen bond-donor molecule incorporating an azo group, and a non-mesogenic alkoxystilbazole moiety, acting as a halogen bond-acceptor. Upon irradiation with polarized light, the complex exhibits a high degree of photoinduce

A conceptually novel materials design, based on crosslinked ferroelectric liquid-crystalline polymers, is demonstrated for efficient switching of a second-order nonlinear optical (NLO) response in the solid state. By controlling the molecular alignment of the NLO moieties through two-photon isomerization of azobenzene molecules, reversible isothermal photocontrol of second-harmonic generation is achieved with contrast of up to 20.

Azobenzene liquid-crystalline (LC) polymers coated on a flexible polymer substrate were directly crosslinked by electron beams (EBs). We demonstrated that EB-crosslinked azobenzene LC polymers could successfully work as photomobile polymer materials with an adhesive-free bilayer structure.

Tunable photonic crystals exhibiting optical properties that respond reversibly to external stimuli have been developed using liquid crystal networks (LCNs) and liquid crystal elastomers (LCEs). These tunable photonic crystals possess an inverse opal structure and are photo-responsive, but circumvent the usual requirement to contain dye molecules in the structure that often limit their applicability and cause optical degradation. Herein, we report tunable photonic crystal films that reversibly t