Fabrication and stimuli response of rice husk-based microcrystalline cellulose particle suspension under electric fields

We report on the electro-responsive electrorheological (ER) properties of microcrystalline cellulose (MCC) particles. It was synthesized from raw rice husk (Downes Rice) through the 3-step preparation of alkali treatment, bleaching, and hydrolysis. The MCC particles with mean particle size about 26 mu m were characterized by scanning electron microscopy, Fourier transform infrared spectroscopy and thermal gravimetric analysis. The MCC particles were then dispersed in silicone oil to create an ER fluid; its dramatic electro-responsive phase changes under an applied electric field were observed by an optical microscopy. The effect of electric field strengths on ER performances of the ER fluid were determined using a rotational rheometer equipped with a high-voltage generator from the controlled shear rate mode and dynamic oscillation measurements. The fluid showed typical ER effects of Bingham fluid behavior with yield stress and viscoelastic properties under an applied electric field.