Templated nanofiber synthesis via chemical vapor polymerization into liquid crystalline films

Abstract

Extrusion, electrospinning, and microdrawing are widely used to create fibrous polymer mats, but these approaches offer limited access to oriented arrays of nanometer-scale fibers with controlled size, shape, and lateral organization. We show that chemical vapor polymerization can be performed on surfaces coated with thin films of liquid crystals to synthesize organized assemblies of end-attached polymer nanofibers. The process uses low concentrations of radical monomers formed initially in the vapor phase and then diffused into the liquid-crystal template. This minimizes monomer-induced changes to the liquid-crystal phase and enables access to nanofiber arrays with complex yet precisely defined structures and compositions. The nanofiber arrays permit tailoring of a wide range of functional properties, including adhesion that depends on nanofiber chirality.

Control of the Folding Dynamics of Self‐Reconfiguring Magnetic Microbots Using Liquid Crystallinity

“…We hypothesized that the disparity in the folding times of microbots (Figure c) is a result of changes in the LC‐free energy arising from elastic strain and topological defects (regions where n is discontinuous), both of which are dependent on surface‐induced ordering of LCs. When microscale inclusions are introduced into a nematic host, the director n around the inclusions is determined by the elastic strain energy of the LC ( K r I ) and the surface anchoring energy ( W r I 2 ) associated with preferential orientation of n at the inclusion surface, where K is the Frank elastic constant of the LC, W is the surface anchoring energy density, and r I is the radius (size) of the microinclusion . For typical thermotropic nematic LCs such as 5CB, K ∼ 10 −12 N and W ≈ 10 −5 to 10 −6 J m −2 .…”

Stimuli‐Responsive Dynamic Metaholographic Displays with Designer Liquid Crystal Modulators

“…For instance, τ and sensitivity to stimuli of the designer LCs can be modulated by simply adjusting d or by using a wide pool of LC materials that differ in internal ordering of LCs and anisotropic characteristics. [24][25][26]32] Integration of the designer LC (d = 10 µm) into spin-encoded metaholograms requires the creation of RCP and LCP output beams that have E-dependent phase delays. To implement such a condition effectively, the incident beam is linearly polarized at 45° (LP 45°) about the rubbing direction with λ = 633 nm (Figure 3a-c).…”

“…Use of designer LC that responds to temperature has an advantage that phase retardation can be easily implemented in the entire visible region without loss of light. To realize the heat-responsive LC-MS, we use E7 (Δn = 0.2116 at 25 °C and λ = 633 nm), [34] which is a mixture of LC compounds composed of several cyanobiphenyls with long aliphatic tails, [23,24,32] with a wider temperature range of nematic phase (−60 to 60 °C) than 5CB (23-35 °C). When heated, the thermal energization causes a reduction in the LC ordering (and thus Δn eff ), which in turn decreases τ in the designer LC cell; this transformation can be exploited to control the polarization of the output beam.…”

Chemical vapor deposited polymer layer for efficient passivation of planar perovskite solar cells

“…Chemical vapor deposition (CVD) polymerization is able to deposit polymer coatings over large surface areas and has been used widely to fabricate consumer products. [40][41][42] Besides the main advantage of being solvent-, plasticizer-and initiator-free, which ensures high purity in the large-area deposition, CVD polymerization allows for a precise thickness control of the polymer layer. 43,44 Additionally, CVD typically results in pinhole-free layers and conformal coating of nanometer sized features.…”