Anomalous dichroism of cellulose nanowhisker embedded composite film

Abstract

While natural nanoparticles are currently being investigated in a wide range of applications due to their compelling strong potential, they have yet to be employed for practical engineering material systems. Here, we demonstrate a dichroic nanocomposite film that shows outstanding optical properties by introducing cellulose nanowhiskers (CNWs) into PVA iodine complex. CNWs were isolated via acid hydrolysis and the nanocomposite film was elongated and dyed with iodine. The significantly reduced extension and treatment time of iodine were applied for the alignment of iodine and PVA molecules in the film. The results revealed that the degree of polarization and transmittance were enhanced as the draw ratio and the content of the CNWs increased. We expect that this material system can offer a new pathway for designing and processing more advanced engineering materials with high performances by using various natural biomaterials.