We propose and implement a technique for arbitrary pattern fabrication in liquid crystal (LC) alignments and local polarization control for light wavefront. A micro-lithography system with a digital micro-mirror device as dynamic mask forms arbitrary micro-images on photoalignment layers and further guides the LC molecule orientations. Besides normal phase gratings, more complex 2D patterns such as quasicrystal and checkerboard structures are demonstrated. To characterize the optical performances of the fabricated structures, the electro-optically tunable diffraction patterns and efficiencies are demonstrated in several 1D/2D phase gratings. Compared to other techniques, our method enables the arbitrary and instant manipulation of LC alignments and light polarization states, facilitating wide applications in display and photonic fields.
Different from the
conventional surface modification strategy,
the end reaction based on the active aldehyde groups of cellulose
nanocrystal (CNC) provides a targeted modification under the protection
of its surface chemistry. With the purpose of promoting its redispersibility
in water, the strategy of triazole end-grafting performed on CNC was
proposed in this study, exhibiting the significant improvement on
the redispersion and stability of nanocrystals in the aqueous suspension
attributed to synergistic effect of steric stabilization and electrostatic
repulsion. The end-modified CNC was then introduced into a natural
rubber (NR) matrix to fabricate the composites with reactive compatibility
from a thiol–ene click reaction. Ascribed to the formation
of covalent linkage between nanofillers and matrix together with the
architecture of the rigid percolating network, the mechanical properties
of obtained composites were remarkably advanced. With the introduction
of 10 wt % end-modified CNC, the tensile strength, Young’s
modulus, and storage modulus of the prepared composite increased by
160, 468, and 1041% in contrast with those of the neat NR material.
More importantly, this composite retained a high level of elongation
at the break (1575%) similar to that of the raw rubber material attributed
to the designed covalent linkage and resultant reactive enhancement
of end-modified CNCs to the NR matrix.
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