Nanocrystalline Cellulose for Anisotropic Magnetoelectric Composites

The emergence of piezoelectric polymers in magnetoelectric (ME) composites enables flexible and low-cost device fabrication though notably gives rise to the highest ME output voltages to date. Accordingly, the highest piezoresponsive polymers, poly(vinylidene fluoride) (PVDF) and its copolymers, are exclusively studied despite an inventory of unexplored piezoelectric polymers such as naturally occurring cellulose, that is only recently demonstrated in ME composites. Herein, the development of nanocrystalline cellulose (CNC)-based ME composites is reported on. Two types of CNC, nanospheres and nanowhiskers, are synthesized and incorporated in laminate composite, which exhibit a giant α ME ( > 1 V cm -1 Oe -1 ). By successfully reconstructing the orientated cellulose fibril structures found in natural plants using spinning-induced alignment of CNC nanowhiskers, an anisotropic effect originating from the piezoelectric phase in ME composites is attained. The anisotropic effect produces output voltages an order of magnitude higher than those in current polymer-based particulate ME vector sensing composites with 0-3 configurations.