Liquid crystalline chitin/poly(acrylic acid) composite, with its unique optical properties, was fabricated by the free-radical photopolymerization of acrylic acid in an aligned mesophase. Alignment of the mesophase was achieved by unidirectional shearing. The developed composites, coated on calcium fluoride (CaF2) substrate, were transparent, and the alignment was retained depending on the mesophase composition of the ternary dispersion (chitin microfibrils, water, acrylic acid). According to studies from polarized FTIR spectroscopy, both the degree of orientation and the molecular interactions were strongly affected by respective mesophase behavior. The average molecular chains of chitin microfibrils were oriented along the shear direction. A high dichroic ratio value of about 25, observed in composites of chitin/poly(acrylic acid) with a w/w ratio of 55:45, opens an interesting avenue to prepare a new chitin-based optically anisotropic composite. (C) 2003 Wiley Periodicals, Inc.