ADSORPTION OF POLYMERIC INCLUSION-COMPOUNDS ON MUSCOVITE MICA

alpha-Cyclodextrin, alpha-CD, which does not adsorb on mica, can be bo und to this surface as a polymeric inclusion compound that is formed b y threading many alpha-CD rings on a cationic polyelectrolyte, poly(de camethylenebipyridinium dibromide). The major driving force of the ads orption of the polymer and the polymeric inclusion compound is ion exc hange with surface ions of mica. Somewhat less polymer is adsorbed whe n it is engaged in the inclusion complex than as pure polymer. The rat es of adsorption for both the polymer alone and for the polymer in the inclusion compound depend strongly on the particular cation initially present at the mica surface (Li+ or K+); it is much more rapid with L i+. The equilibrium between complexed alpha-CD and uncomplexed alpha-C D, found in solution, is modified upon adsorption of the complex to fa vor the release of alpha-CD from the complex. However, the alpha-CD is only slowly released from the complex on the surface and, as a result , mica-bound complex can be isolated.