Abstracts Book - IMRC 2018

• SWS-O004
NANOCSELLULOSES WITH TUANABLE AMPHIPHILICITY AND
CHEMICAL FUNCTIONALITIES
You-Lo Hsieh 1
1 University of California, Davis, Fiber and Polymer Science, United States.
Nanocelluloses are crystalline domains isolated various plant, animal and
microbial sources. These one dimensional (1D) nanocelluloses have shown to
exhibit wide ranging geometries and surface chemistry depending upon their
origins and/or methods of isolation. For instance, regio-selective C6 hydroxyl by
2,2,6,6-tetramethylpyperidine-1-oxyl (TEMPO) mediated oxidation coupled with
shear force has shown to convert 97% of rice straw cellulose into 1-2 nm wide
and up to 1 mm long cellulose nanofibrils (CNFs). These CNFs are not only
amphiphilic but can also be tuned to be surface charged to varying degrees to
act as surface active agents, coagulants for cells, antibacterial agents for
microbes, templates for nano-particles and nano-prisms as well as to be capable
self-assemble into various 2D and 3D structures, such as fibers, hydrogels,
organogels, hybrid interpenetrating gels, thin film and aerogels, etc. Aerogels
assembled these CNFs are not only ultra-light (as low as 1.7 mg/cm 3 ) and ultraporous
(to over 99.9%) but amphiphilic and super-absorbent, absorbing up to
375 times of water and hydrocarbons. Chemical crosslinking or vapor deposition
may further tune these aerogels to be hydrophobic, capable of differential
absorbing, removing or filtrating hydrocarbons aqueous systems. We have also
designed new chemical means to simultaneously introduce targeted surface
reactive and functional groups in generating novel nanocelluloses. These
streamlined defibrillation processes may be tuned to generate either rod-like
cellulose nanocrystals (CNCs) or CNFs, offering versatile as well as green
alternative to the existing processes. Biopolymers are synthesized by living
organisms in a variety of sophisticated structures that serve as excellent
precursors as well as inspiration for advanced materials. Biological
nanomaterial innovations will not only meet future demand in novel, better and
sustainable materials but also help to minimize negative environmental impact
our food and energy supply chain.