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We present a 1D/2D switchable grating based on field-induced polymer stabilized blue phase liquid crystal (PSBPLC). For 1D grating, the diffraction efficiency of the first order is 37.2% and the phase modulation depth of the 1D grating can achieve 2π. For 2D grating, more than 90% of light intensity is distributed to the surrounding orders of zero order and the phase modulation depth is about 3.67π. Furthermore it shows fast phase modulation and 1D/2D switching time.

Electrospun nanofibers have shown great potential in wide applications such as energy, filtration, medical devices, and sensors. For all these applications, fiber morphology, fiber diameter and pore size of electrospun fiber mat play critical roles in determining the performance of the final products. Research has proved that sonic vibration can dramatically improve the electrospinnability of polymer solutions and subsequently the resultant fiber properties. In this work, the effects of sonic vibration on fiber morphology as well as fiber diameter and the pore structures of electrospun polyacrylonitrile fiber mat were investigated. The relationships between sonic vibration and fiber diameter, and pore size of the electrospun fiber mats were also studied.

The major topic covered in this paper is fabrication and performance study of polyacrylonitrile (PAN) ultrafine fibers from high-concentration solutions via a vibration-electrospinning technique. The influences of ultrasonic vibration on the solution properties of high viscous PAN solution as well as surface morphology and mechanical performance of PAN fibrous mats were investigated. The results indicated that: (1) the effect of ultrasonic vibration on the mechanical properties was significant; (2) the vibrorheological effects of ultrasonic vibration appeared not only in dramatic reduction of polymer viscosity, but also in improvement of the electrospinnability of polymer solutions; (3) fibers with smaller diameter, better uniformity and fewer surface defects were prepared with the application of vibration; and (4) the tensile strength of membranes was substantially enhanced at optimized vibration parameters comparing that without vibration treatment.

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