Research Projects

Conventional polymer-dispersed liquid crystal (PDLC) smart windows typically use apolar nematic liquid crystals (LCs). These apolar nematic LCs respond to electric fields due to their coupling with the dielectric anisotropy. However, they are diamagnetic in nature and require very high magnetic fields (~1T) to elicit a response, which limits their practicality for real-world applications. Additionally, these LCs exhibit moderate switching times of the order of milliseconds. Recent breakthroughs in true 3D ferrofluids—specifically ferroelectric nematic (N_F) and ferromagnetic nematic (N_M) LCs offer promising solutions to these limitations. The N_F phase was first discovered experimentally in 2017 by Mandle et al., over a century after Max Born’s theoretical prediction in 1916. Ferroelectric nematic LCs exhibit remarkable properties, including spontaneous ferroelectric polarization exceeding 6 μC/cm^2 , dielectric constants above 10⁴, and sub-microsecond switching times. Similarly, the ferromagnetic nematic LC phase was realized experimentally in 2014 by Alenka et al., four decades after its theoretical prediction. This was achieved by dispersing anisotropic ferromagnetic nanoplatelets into a nematic host, resulting in a fluid system that exhibits spontaneous magnetization and long-range magnetic ordering. Combining these ferrofluids gives rise to novel multiferroic materials that simultaneously exhibit two or more ferroic properties—such as ferroelectricity, ferromagnetism, and ferroelasticity—in a single phase. These materials are highly responsive to external stimuli. The coupling between ferroelectric and ferromagnetic properties enables dual-field switching under very low fields (less than 0.1V/μm, less than 10 mT) with ultrafast (microsecond-scale) response times. Currently, most smart windows operate solely under electric fields (~5 V/μm) and exhibit moderate switching times (~milliseconds). One major challenge is ensuring compatibility between ferrofluids and polymers, which is critical for maintaining ferroic order within the polymer matrix. The proposed topic is novel and still in its early stages of development. There are only a few studies on multiferroic liquid crystals. While polymer-dispersed liquid crystals are well established, the integration of multiferroic LCs into polymer matrices has not yet been explored. In this project, we first aim to synthesize multiferroic LCs, and then embed them in a polymer matrix to create polymer-dispersed multiferroic liquid crystals (PDMLCs). These PDMLCs are expected to operate under very low electric and magnetic fields, with switching times on the order of microseconds. This work holds strong potential for energy-efficient applications such as smart windows, projection displays, wireless switchable devices, and tunable lenses, while also contributing to the fundamental understanding of multiferroic soft matter systems.