Research

 Research Vision 1: Human Health

Through material innovations in soft materials, we aim to tackle the challenges in human health by creating a mechanically compliant interface between human and engineering devices. 

Research Vision 2: Climate Change

Through material innovations in adaptive materials, we aim to tackle the challenges in climate and energy by generating passive systems that only consume renewable energy. 

Research Topic 1: Hydrogels Interact with Bacteria

Engineered Living Hydrogels

3D printed living materials with a high resolution. To convert the benchtop technology to real-world applications, we adopted hydrogels as matrix materials for genetically engineered bacteria. The hydrogels ensured the viability, functionality, and safety of living bacteria. They were 3D-printed into large-scale (in centimeters), high-resolution (in microns) structures with precise control over spatiotemporal responses. Based on this fundamental principle, a few living devices, such as wearable or ingestible living sensors were fabricated as biosensor prototypes for various biomarkers. 

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Research Topic 2: Hydrogels Interact with Force

Anti-Fatigue Soft Materials

Fatigue-resistant soft materials that sustain repetitive stretches. Inspired by the architectures of the muscle and cartilage, we proposed the structural fundamental principles for soft materials with fatigue resistance. Implementation strategies include nanocrystals by thermal annealing and nanofibers by phase separation. We found that these polymer nanostructures can effectively pin the crack propagation in soft materials, with the fatigue threshold increased by two orders of magnitude.

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Ingestible Devices for GI Tract Monitoring

Self-deployable actuators that transform and retain in the GI tract. We designed an ingestible pill that, upon reaching the stomach, quickly swells to the size of a soft ping-pong ball big enough to stay in the stomach. The pill was embedded with a sensor that continuously tracks the stomach’s temperature for 30 days.

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Research Topic 3: Hydrogels Interact with Light

Implantable Optical Fibers for Light Delivery

Stretchable optical fibers that deliver light to nerves. We developed a light delivery strategy that facilitates light transmission to the unconstrained sciatic nerve along with persistent muscle stretching for four weeks. We fabricated fatigue-resistant hydrogel optical fibers. Besides the mechanical performance, hydrogel fibers with polymer nanocrystals exhibit high transparency and a high numerical aperture for efficient light transmission.

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Research Topic 4: Hydrogels Interact with Mass

Hydrogels to Capture Atmospheric Water

Phase-change hydrogels that capture water from the air. We developed hydrogels that exhibit crystalline-amorphous structure transition and inverse temperature dependence of water sorption, enabling moisture capture at elevated temperatures to prevent dehydration and enlarge the tunability of water uptake.

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Sorbent Materials for Thermal Regulation

High water uptake and adsorption enthalpy of the hydrogel/salt composite. We developed a thermal energy storage device based on the adsorption of a hydrogel/salt composite, promising high energy densities over 200 kWh/m3, desorption at ≤ 70˚C and achieving building energy savings of ≥ 50 kWh/m3/day. We leveraged a unique hydrogel/salt composite in a high-performance architecture consisting of an integrated adsorbent bed and evaporator/condenser to maximize thermal storage capability and fast cycling.