ELECTRONIC-PROPERTIES AND OPTICAL-PROPERTIES OF WET-SPUN FILMS OF LI-HYALURONATE AND NA-HYALURONATE

The uv absorption of Na-hyaluronate (NaHA) films and the refractive in dices, water content, and swelling of LiHA films have been measured as a function of relative humidity. Three peaks are observed in the uv a bsorption of NaHA (at about 250, 310, and 330 nm) for water content ab ove 10 water molecules per disaccharide. The absorptivity of the 250, 310, and 330 nm peaks increase as the water content increases, indicat ing a change in the electronic properties of the HA molecule. The refr active indices, water content, and swelling of LiHA films are used to determine the optical polarizability via the Lorentz-Lorenz relation. The polarizability of LiHA is found to have a similar dependence on wa ter content as NaHA, though the changes observed are larger in magnitu de. (C) 1994 John Wiley and Sons, Inc.