Project Leader

You-Lo Hsieh, professor of fiber and polymer science, Division of Textiles and Clothing, UC Davis

Specific research objectives were to:

• Optimize aerogel properties and production efficiency.

• Develop processes to incorporate nanocellulose-assembled aerogels and fibers into scalable and industrial/consumer products.

• Expand functional materials from nanocellulose, silica, and porous carbon.

Amphiphilic superabsorbent aerogels

Novel rice straw cellulose nanofibril (CNF) aerogels have been developed and are the lightest among all aerogels, natural or synthetic, reported to date. They are superabsorbent of both water and oils. These aerogels can be tuned to be superhydrophobic, capable of selective absorption and removal of organic solvents and oils from water. Potential applications include oil spill cleanup and refined organic-aqueous separation. As these aerogels only utilize two-thirds of their pore capacity, further research is being conducted to maximize aerogel absorption to full capacity.

Imaging work shows how nanocellulose can coagulate microscopic pathogens and potentially open the door to new diagnostic tools

Product development

Hybrid membranes were developed with CNF-bound silver nanospheres and nanoprisms. These products displayed a shape-regulating ability and were easily fabricated into freestanding films with desirable light-scattering properties.

With their superior water-absorbing capacities and resiliency, nanocellulose aerogels could be used to bind enzymes for use as recyclabe biocatalysts in both aqueous and organic media. Researchers used two approaches to bind a lipase enzyme to CNF aeorgels: adsorption on to dry aerogel and premixing in CNF suspension. Further optimization of enzyme binding and loading is needed.

These highly crystalline rice nanocellulose fibrils and rods have also been proven very effective in reinforcing nanofibrous webs and thin films.

CNFs were also incorporated into an aqueous polyvinyl alcohol solution and electrospun into a water insoluble nanofibrous web.

Functional materials

Nanocellulose surface areas can filter microscopic organisms. Researchers studied the ability of CNFs to coagulate pathogens. Silver nanoprisms bound to CNFs inhibited microbial growth at high levels and agglomerated bacteria cells at low levels. This suggests a potential dual function for antimicrobial and microbial detection applications.

In other work, silica nanoparticles were synthesized from a cellulose isolation process.