A simple technique for measuring the refractive index of polymer latexes at various wavelengths

The refractive index of emulsions of polymers and copolymers may be estimated from absorbance readings with a UV-visible spectrophotometer. Other information needed is the weight-average particle diameter, from other techniques such as gradient disc centrifugation. A simple computer program matches the refractive index parameter so that calculated and experimental absorbances are equal at the given wavelength. The wavelength dependence of the polymer refractive index is readily obtained.