Taking a highly interdisciplinary approach, our group employ a combination of theoretical, numerical and experimental approaches to study the fundamental mechanics and physics of materials and phenomena encountered in nature and engineering process, and to invent novel materials, electronics, and machines capable of extraordinary functions with advanced technologies. Our current research includes the following three research thrusts: 1) mechanics of soft materials & soft machines, 2) design and fabrication of flexible/stretchable/printed electronics, and 3) 3D/4D printing of multifunctional materials.
Soft Materials & Soft Machines
Most biological materials (e.g. muscle, tendon, membrane, nerves) and many man-made materials (e.g. polymer, elastomer, hydrogel) are ‘soft’: i.e. elastic and easily deformed. Compared with ‘hard’ materials (e.g. steel, concrete, carbon nanotube), soft materials are usually capable of nonlinear and large deformation and can even response to external stimuli, such as mechanical force, temperature, light, or electrical field. These unique properties offer opportunities for discovery and invention that could lead to breakthroughs in engineering and technology. Understanding the properties and mechanism of soft materials is of paramount importance to fully utilize and integrate them with hard materials into functional machines for a variety of novel applications, such as actuators, energy-harvesters, tunable lenses, artificial muscles, drug delivery, wearable electronics and soft robotics.
In this research thrust, we are aiming to develop active materials, structures and devices that can reversibly change their shape, color, and functionalities on demand by applying external stimuli (light, temperature, electric and magnetic field or pH change). A number of recent technologies have been brought together to enable a breakthrough in material performance. These technologies include: multi-material 3D/4D printing, advances in materials science and new capabilities in simulation and optimization. We envision developing novel structures and machines, which are able to respond on demand by changing its shape and/or physical properties.
We are also interested in biomechanics of biological materials and structures to develop new biomedical devices for improving human wellbeing, such as urinary catheters, artificial cartilage, and coronary stent etc.
Flexible, Stretchable, Printed Electronics System
Recent advances in mechanics designs and materials science have boomed an emerging field of stretchable/wearable electronics, which can sustain large deformations and conform to surfaces with complicated geometries or even biological tissues while maintaining normal functions and reliability. This technology creates new opportunities in consumer electronics and bio-integrated devices, with examples ranging from flexible displays, stretchable circuits, to strain sensors and epidermal electronics.
In this direction, we are integrating mechanical principles and additive manufacturing techniques to fabricate high-performance, robust but cheap electronics (transistors and sensors) and energy-storage devices (supercapacitors) capable of extreme deformations without sacrifice of high performance. In the long run, the developed stretchable electronics will be integrated with the biological tissues/organs for monitoring their activity, detecting diseases and offer effective therapies.
3D/4D Printing & Bioinspired Materials
Additive manufacturing (3D printing) has been widely used in all kinds of rapid prototyping as well as by hobbyists and companies to make finished products and can print not only plastic but also metal, ceramics, and even biological tissue. On the other hand, many nature materials and structures exhibit unprecedented surface, optical, mechanical and thermal properties, such as self-cleaning of gecko feet, superhydrophobicity of lotus leaf, ultra-hardness of turtle shell, as well as vivid structural colors of butterfly wing.
In this thrust, our group explore and biomimetic the natural materials & structures with remarkable properties or functions using additive manufacturing (3D/4D printing), self-assembly, and micro-/nano-fabrication techniques. With special attention to the fundamental physics and mechanics, our long-term goal is to design and optimize synthetic materials and structures to address the grand challenges we are facing nowadays, ranging from durable infrastructure to energy storage and medical treatment.