A Direct Method of Studying Polymer Adsorption on to Mica Surfaces Using a Commercial Mettler Ultramicrobalance

A simple and direct method has been developed of determining absolute values of adsorbance, i.e. mass per unit area, of polymers adsorbed from solution on to mica surfaces. A commercially available Mettler UMT2 ultramicrobalance is used to measure the weight of mica sheets before and after the immersion of the mica sheets into polymer solution for a given period of time. The increase in weight of mica sheets is divided by the total area of mica surfaces to derive the adsorbance. Practically measurable change in adsorbance was evaluated to be 0.1 mg m2. As an example of the practical application of the present method, an experimental result is presented of the adsorption kinetics of polystyrene (M=66,000) adsorbed from cyclohexane on to mica surfaces at the 0 -temperature.