What We Study

Ferroelectric Nematic Liquid Crystals

The recently discovered ferroelectric nematic (N_F) phase combines giant spontaneous polarization (over 0.04 C/m²) and enormous dielectric constants with sub-millisecond switching — opening applications in high-power supercapacitors and low-voltage, fast electro-optical devices. In chiral-doped mixtures, the selective reflection color can be reversibly tuned by very small in-plane fields (0.02–0.1 V/µm), enabling backlight-free displays, smart windows, shutters, and e-papers.

We also explore the rich fluid behaviour of the N_F phase: pancake-shaped droplets that drift and deform in weak electric fields, sessile drops and fluid bridges that show fingering instabilities, thermally driven "thermo-motors," and freestanding ferroelectric filaments stabilized by fields three orders of magnitude smaller than in ordinary dielectric fluids.

The same giant polarization makes the N_F phase intrinsically piezoelectric: mechanical strain couples linearly to polarization, giving a fluid material that converts between mechanical and electrical energy — a "liquid piezoelectric" effect with no solid-state analogue.

Electro-Active Ionic Elastomers

Motivated by the low-voltage actuation of ionic electroactive polymers, we develop ionic elastomers — ionic polymer electrolyte membranes (iPEM) and ionic liquid crystal elastomers (iLCE) — that bend under AC or DC voltages below 1 V. Our iPEMs outperform most well-developed ionic EAPs, while even un-optimized iLCEs are already comparable.

Ionic liquid crystal elastomers add a unique advantage: alignment-dependent actuation, which allows actuation patterns to be pre-programmed during cross-linking. Thermal, optical, and electric actuation are all possible. We also study compliant electrodes and soft-robotic applications.

Flexo-Ionic Effect of Ionic Liquid Crystal Elastomers

Flexoelectricity couples electric polarization to a strain gradient, studied in both crystals and liquid crystals since the 1960s. A related but much larger effect arises in ionic materials, where the polarization comes from the displacement of differently sized cations and anions — yielding very large flexo-ionic coefficients (29–323 µC/m).

Such a large response is promising for soft robotics, sensors, and micro power generation. We study the flexo-ionic effect in a new class of ionic liquid crystal elastomers, characterizing elastic modulus, phase transitions, ionic conductivity, and morphology, and how molecular alignment controls the flexo-ionic coefficients.

Liquid Crystal Elastomer Mechanics

Beyond electrical and ionic actuation, we study how liquid crystals reshape the mechanical properties of the elastomer networks that contain them. Dispersing low-molecular-weight liquid crystal inclusions into an elastomer matrix can dramatically stiffen the network, while swelling a liquid crystal elastomer with a low-molecular-weight liquid crystal solvent drives controlled, reversible shape changes.

These effects let us tune stiffness and shape independently of chemical cross-linking density, opening routes to soft actuators and structural materials whose mechanical response is programmed by the liquid crystal phase itself rather than by the polymer backbone alone.

Microlens Arrays

Liquid-crystal-based microlens arrays have attractive applications in optoelectronics, integrated optics, optical fiber switches, information processing, optical communications, and imaging. Most existing LC microlens arrays require delicate fabrication.

We study cholesteric liquid crystal microlens arrays in different configurations that show unique geometrical and optical properties, focusing on simple, cost-effective fabrication using different cholesteric mixtures and on the optical capabilities of the lenses for a range of applications.

LC Spherical Caps in Magnetic & Electric Fields

We study, experimentally and theoretically, the director structure of nematic liquid crystal drops forming spherical caps under magnetic and electric fields, starting from a director perpendicular to the air and glass boundaries. Above a threshold field a metastable inversion wall forms in the middle of the drop and then moves outward; under high-frequency (>120 Hz) electric fields the defect wall rotates parallel to the field.

The linear displacement of the field-induced defect wall, together with the deformation threshold, lets us determine both the bend elastic constant and the rotational viscosity. Drops with uniform director structure can act as tunable optical lenses whose focal length is controlled by light polarization, viewing angle, and magnetic or electric fields.

Energy Storage & Electrochemical Devices

Ionic liquid crystal elastomers are also excellent solid electrolytes: their ordered ion channels support fast ion transport while remaining mechanically robust. We use them as gel-polymer electrolytes for lithium-ion batteries, where molecular alignment improves ionic conductivity and cycling stability over conventional disordered polymer electrolytes.

The same ionic liquid crystal elastomer electrolytes work as the solid electrolyte layer in organic electrochemical transistors (OECTs), enabling flexible bending sensors and structural-health-monitoring composites. We also study electrocaloric effects at ferroelectric and antiferroelectric phase transitions in bent-core and ferroelectric nematic liquid crystals for high-power capacitors and solid-state cooling.

Responsive Liquid Crystal / Polymer Fibers

Using airbrushing, electrospinning, and force spinning of homogeneous LC/polymer solutions, we make piezoelectric and responsive composite fibers. Quantitative measurements show that vapors such as toluene and acetone pass through the polymer sheath and are absorbed by the liquid crystal in the core, changing the fiber mat's optical properties — enabling sensitive, reversible detection of volatile organic compounds.

A simple process clads conventional monofilament fibers with low-molecular-weight liquid crystals stabilized by an outer polymer sheath. These fibers keep the responsiveness of the LC in a flexible, drapable format, and the monofilament core makes them far more rugged, with a magnified response to external stimuli. Their sensitivity can be tuned by varying the liquid crystal composition.

Textiles & Wearable Sensors

Building on our liquid-crystal-clad monofilament fibers, we develop fabrics that retain the responsive properties of liquid crystals in a flexible, drapable format. The monofilament core makes the fibers rugged with a magnified response to external stimuli compared to earlier electrospun or airbrushed LC-core fibers.

The sensitivity of individual fibers can be tuned over a broad range by varying the liquid crystal composition. Complex fabrics can be woven from fibers that respond to temperature, chemical concentration, and pressure — and fashioned into garments that sense and report the wearer's health or environment.

Biological Sensing with Liquid Crystals

Liquid-crystal-based biosensors exploit the high sensitivity of liquid-crystal alignment to amphiphiles adsorbed onto an LC surface from water. They offer inexpensive, easy optical detection of biologically relevant molecules such as lipids, proteins, and cells.

The techniques use linear or circular polarizers to read out the alignment of the liquid crystal, translating molecular binding events into clear optical signals — and we have demonstrated antigen detection with sensitivity comparable to ELISA.