We report a thin-film optical diode written into thin films of a liquid-crystalline polymer (LCP), which is based on the photoinduced LC-to-isotropic phase transition of LCPs. The interference pattern between a collimated and a focused UV laser beam is imprinted as chirped volume-phase gratings in photoresponsive LCP films and no further processing steps like development or liftoff are required for the fabrication. The resultant thin-film device not only possesses the fundamental functions of an optical lens for laser beam focusing, but also shows diode effects with the focusing/defocusing function dependent on the direction of light incidence and orientation of the device. Furthermore, this photonic thin-film lens exhibits a spatially tunable spectroscopic response, revealing a unique physics of secondary excitations of resonance modes of the single-layer LCP waveguide grating structures. This reveals the mechanisms for the focusing/defocusing of laser beams by chirped grating structures. Erasability and reconstructibility of the photoresponsive LCPs guarantee rewritability of the thin-film diode lens.

A phototunable laminated liquid crystal film with simultaneous multicolor reflection is successfully fabricated by doping a light-driven chiral molecular switch into the laminated cholesteric liquid crystal structure. Upon UV-light irradiation, the reflection notches and their hyper-reflectivity properties can be precisely tuned, and their original state can be properly returned by visible-light irradiation.Keywords: cholesteric liquid crystal film; hyper-reflectivity; laminated structure; light-controllable property; polymer-stabilized liquid crystals; simultaneous multicolor reflection;

A chiral nematic liquid crystal–photopolymerizable monomer–chiral azobenzene compound composite was prepared and then polymerized under UV irradiation. The reflection wavelength of the composite can be extended to cover the 1000–2400 nm range and also be adjusted to the visible light region by controlling the concentration of chiral compounds.

Electro-optical switching with low voltage, no hysteresis and fast response speed is achieved in polymer-stabilized nanoparticle-enriched blue phase liquid crystals with a wide temperature range, and it is found that the benefits from the combined method are more than from the simple addition of polymer stabilization and nanoparticle dispersion.

A controllable and reversible broad-band reflector can be obtained by virtue of the response of one-dimensional (1-D) nanomaterials in chiral nematic liquid crystalline media to an external electric field. The colour switching originated from the electro-responsive 1-D nanomaterials and the responsive mechanism was discussed based on the relationship between the pitch distribution and the alignment of nanomaterials.

A new series of azobenzene-dimers were synthesized and doped into the blue phase liquid crystals to broaden the temperature range of BPs. It is found that not only can the reflection wavelength of BPI be reversibly controlled but BPI can also be transformed into the cholesteric phase owing to isomerization of azobenzene induced by light.

Several kinds of tolane cyano derivatives with different lateral fluoro substituents are doped with chiral additives to induce the blue phase (BP). Fluoro substituents are found to exert a great effect on the BP ranges for biphenyl mesogens. The laterally difluorinated compounds exhibit wider BP ranges than their corresponding mono-fluorinated homologues when equal chiral dopant is added, while the non-fluorinated compounds show direct isotropic (Iso) to chiral nematic (N*) transitions, even in highly chiral systems. By adjusting the concentrations of the chiral dopant ISO(6OBA)2 in the fluorinated liquid crystals, the BP ranges can be broadened to more than 12 °C. Competition between the steric repulsions caused by the lateral fluoro substituents and π–π interactions of the aromatic cores is supposed to be the main factor that leads to the above results. Apart from this, a weak C–H⋯F interaction may have also been conducive to the BP stabilization.

Liquid crystalline microphase formed in PEG/lecithin hydrogels provides suppressed release of hydrophilic drugs but accelerated release for lipophilic drugs, achieving quasi-zero-order release of drugs with different water solubility.

A chiral nematic liquid crystal–photopolymerizable monomer–chiral azobenzene compound composite was prepared and then polymerized under UV irradiation. The reflection wavelength of the composite can be extended to cover the 1000–2400 nm range and also be adjusted to the visible light region by controlling the concentration of chiral compounds.

Electro-optical switching with low voltage, no hysteresis and fast response speed is achieved in polymer-stabilized nanoparticle-enriched blue phase liquid crystals with a wide temperature range, and it is found that the benefits from the combined method are more than from the simple addition of polymer stabilization and nanoparticle dispersion.

A controllable and reversible broad-band reflector can be obtained by virtue of the response of one-dimensional (1-D) nanomaterials in chiral nematic liquid crystalline media to an external electric field. The colour switching originated from the electro-responsive 1-D nanomaterials and the responsive mechanism was discussed based on the relationship between the pitch distribution and the alignment of nanomaterials.

A new series of azobenzene-dimers were synthesized and doped into the blue phase liquid crystals to broaden the temperature range of BPs. It is found that not only can the reflection wavelength of BPI be reversibly controlled but BPI can also be transformed into the cholesteric phase owing to isomerization of azobenzene induced by light.