Research

Our research group mainly focuses on complex fluids and its technology applications. Relying on the interdisciplinary background (including physics, materials, chemistry, optics and mechanics) and utilizing various manipulation approaches (such as electric, optical, magnetic and thermal fields), particularly we are exploring complex fluids from two perspectives: one perspective is the basic research to explore physical phenomena and the underlying mechanisms (including droplets, bubbles , vapor steam, electroosmotic flow, electrolyte, fluid instability, etc.); the other perspective is the relevant technological applications for the sustainable environment, energy and among others (such as nanotechnology, desalination, solar steam, water purification and treatment, etc.).

Ongoing projects in our group (2016-)

1. Shock electrodialysis

2. Steam and bubble induced by light

3. Liquid bridge under electric filed

4. Instability of a liquid film

5. Others: magnetic droplets, hydrophobic and hydrophilic surface

Previous research topics (Before 2016)

1. Electrokinetics and shock electrodialysis for desalination

The availability of fresh water as a global concern demands advances in water purification technologies. The most difficult step is the removal of dissolved salts, especially multivalent ions. Reverse osmosis is widely used for large-scale seawater desalination, but electrochemical methods, such as classical electrodialysis and capacitive deionization, can be attractive for brackish or wastewater treatment and for use in compact, portable systems.

Based on a nonlinear electrokinetics phenomenon that a “deionization shock” can propagate through the microstructure, leaving in its wake an ultrapure solution, nearly devoid of co-ions and colloidal impurities, a novel electrodialysis, shock electrodialysis in a porous medium was developed. The advantages of shock electrodialysis include efficient desalination, size-based filtration, charged-based separation, and even disinfection simultaneously achieved within one step.

2. Fluid instability and in-fiber nanostructures

Capillary instability, or breakup of a cylindrical liquid thread into a series of droplets, is perhaps one of the most ubiquitous fluid instabilities and appears in a host of daily phenomena from glass-wine tearing and faucet dripping to ink-jet printing. The study of this Plateau-Rayleigh capillary instability has a long history of over 150 years.

An intriguing thin-film fluid instability during thermal drawing was observed. This instability has two unexpected merits. First, the breakup occurs exclusively along the transverse direction. Secondly, the axial continuity remains intact. A general theoretical frame work to guide materials selection was built to shed insight into more sophisticated nanostructures. This instability can be facilitated by thermal drawing with the inherent scalability to attain the production of well-ordered and globally oriented nanostructures including nanowires and nanoparticles. Remarkably, this methodology has been extended to produce nanostructures made of silicon and other semiconductor components, paving the way for the in-fiber hybrid nanodevices.

3. Magnetic pattern and data storage

Research on magnetic nanostructures for data storage in the commercial market has been developing rapidly in the last two decades. Many experimental properties of magnetic nanostructures, including exchange bias and antiferromagnetic domains, are complicated due to the electron charge and spin freedoms. A series of theoretical work was performed to investigate the physical mechanism of these properties. Particularly, by extending the band gap from electron and photon to magnon, the magnon energy gap was proposed in an artificial structure for spintronics application.