Gradient polymer-disposed liquid crystal single layer of large nematic droplets for modulation of laser light.

The light modulating ability of gradient polymer-disposed liquid crystal (PDLC) single layer of large droplets formed by nematic E7 in UV-cured polymer NOA65 is studied. Operating at relatively low voltages, such PDLC film with a of thickness 10-25 μm and droplet size up to 50 μm exhibits a good contrast ratio and is capable of producing a large phase shift for the propagating coherent light. For a linearly polarized He-Ne laser (λ=633 nm), an electrically commanded phase shift as large as π/2 can be obtained by the large-droplet region of the film.

Chirality of lipids makes fluid lamellar phases piezoelectric.

The role of chirality in membrane-forming lipids is not well appreciated at present. Here we demonstrate that the chirality of phospholipids makes fluid lipid bilayers piezoelectric. Thus, chiral lipids would play a central role in the functioning of cell membranes as active mechanotransducers.

Electricity and mechanics of biomembrane systems: flexoelectricity in living membranes.

Flexoelectricity provides a reciprocal relationship between electricity and mechanics in membranes, i.e., between membrane curvature and polarization.

Flexoelectricity of model and living membranes.

The theory and experiments on model and biomembrane flexoelectricity are reviewed. Biological implications of flexoelectricity are underlined. Molecular machinery and molecular electronics applications are pointed out.

Flexoelectricity and elasticity of asymmetric biomembranes.

In view of the well-established charge and dipolar asymmetry of the two leaflets of a native membrane, the theory of flexoelectricity (and curvature elasticity) is extended to take into account this asymmetry using linear and nonlinear forms of the Poisson-Boltzmann equation. The results are discussed with respect to data from atomic force microscopy studies of electromotility in biomembranes.