We demonstrate a full-color-capability reflective display using red, green, and blue sub-pixels of polymer-stabilized blue phase liquid crystal (BPLC) with different pitch lengths. Vivid colors originate from three-dimensional BPLC photonic crystalline structure. Surface alignment plays a key role to generate uniform and saturated colors in the voltage-off state. Analogous grayscale is achieved by the electric-field-induced unwinding of double-twist structure. This working principle is drastically different from the phase retardation effect of conventional liquid crystal displays. Moreover, the submillisecond response time enables crisp video displays without image blurring. Potential applications for reflective 3D display are also analyzed. V

A polymer-stabilized blue-phase liquid crystal (BPLC) with microsecond response time is demonstrated using a vertical field switching cell. The measured decay time is 39 μs at room temperature (21 °C) and then decreases to 9.6 μs at 44.3 °C. Such a response time is 1-2 orders of magnitude faster than that of a typical BPLC device. The responsible physical mechanisms are the collective effects of short pitch length, strong polymer network, and low viscosity through temperature effect. The on-state voltage of our BPLC device is 44.2 V, hysteresis is below 0.7%, and contrast ratio is over 1300:1.

Dendrons Gn-Cl and Gn-NH (n = 2-4) and novel dendrimers Gn-N approximately N-Gn (n = 2-4) based on triazine and piperazine units were efficiently prepared in good yields without employing the protection and deprotection processes and are fully characterized by 1H NMR and 13C NMR spectroscopies, elemental analysis, and mass spectroscopy. These compounds are transparent and possess good thermal stability. G4-Cl shows a monotropic columnar phase in a narrow range with a coexisting crystalline phase. Dendron G4-NH shows a rectangular column-phase, and dendrimer G4-N approximately N-G4 exhibits a monotropic hexagonal columnar phase. These identifications were supported by the polarizing optical scope and powder XRD studies.

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