Adsorption behavior of amphiphilic polymers - 1. Chromatographic and thermogravimetric characterization

The work reported here involves a study of the adsorption behavior of some amphiphilic polymers containing alternating copolymers of stearyl methacryl ate, mono-n-octylitaconate, styrene, and 1-octadecene with maleic anhydride . We have employed chromatographic and thermogravimetric measurements in or der to characterize the adsorption process, Silica gel was the stationary p hase in the case of the polar column, and a mixture of THF/toluene or chlor oform/toluene as the mobile phase. Toluene content in the mobile phase affe cts the capacity to desorb the polymer from the interface, The adsorption o f the polymers onto silica substrates from toluene between other solvents h as been measured also with static experiments. The results are discussed in terms of the incorporation of hydrophilic groups as maleic-anhydride or hy drophobic groups as stearyl and n-octyl chains. The solvent effect was also considered. Comparison of the adsorption isotherms for PA-18 onto hydrophi lic substrate (Aerosil 200) from two different solvents shows strong compet ition of TKF with the surface functionality of the substrate by the PA-18. (C) 1999 Academic Press.