Limiting thickness of an adsorbed polymer chain. Random flight model

摘要

The probability density of the span of anNhyphen;step adsorbed polymer chain in the direction normal to the solution surface is derived in de Gennesrsquo; model for weakly adsorbed chains. It is noteworthy that the following two different measures of thickness of an adsorbed polymer chain have a differentNdependence. The average span is proportional to lnN, and the scale length of the exponential step density distribution is independent ofN. The average span is identically equal to the distance from the adsorbing solution surface at which the exponential step density obtained in the de Gennes model is equal to unity.