ドテシル硫酸ナトリウムと非イオン性高分子との水溶液中における結合熱

概要

論文の詳細を見る
In order to elucidate the behavior of sodium dodecyl sulfate (NaDS) bound on nonionic polymers, the molar enthalpy of binding of NaDS on polymers, ΔH^^-_<bound>, as well as the amount of bound NaDS, n_<bound>, in 1 kg of 0.5% aqueous solutions of poly (vinylpyrrolidone) (PVP) and poly (vinyl alcohol) (PVA) with various NaDS concentrations at 25° and 37° was determined by means of calorimetric and equilibrium dialysis measurements, respectively. The n_<bound> isotherm against the total concentration of NaDS showed S-shaped curves with PVP as well as PVA at both temperatures. By considering the data of ΔH^^-_<bound> and n_<bound> as a whole, two regions with respect to the behavior of NaDS bound on polymers could be distinguished, corresponding to the smaller absolute values of n_<bound> and ΔH^^-_<bound> (I) and to the larger values (III). Between these, an intermediate region (II) exists. The values of ΔH^^-_<bound> in the regions (I) and (III) were -0.2 (I) and -0.55 (III) kcal・mol^<-1> at 25°, -1.2 (I) and -2.2 (III) kca1・mo1e^<-1> at 37° in PVP-NaDS system, and -0.2 (I) and -0.45 (III) kcal・mol^<-1> at 25° in PVA-NaDS system, respectively. The number of NaDS bound on a single polymer chain of PVP or PVA was found to be confined to 0-16 in the region I and reach the micellar number of NaDS, i.e., 50-120 in the region III. Also, the difference in ΔH^^-_<bound> between regions I and III was found to be nearly equal to the molar micelle formation enthalpy of NaDS in aqueous media. From these results, it was inferred that the bound NaDS molecules behave independently of each other on polymer chains in the region I, while they behave co-operatively to form micellelike aggregates in the region III.
公益社団法人日本薬学会の論文
1975-07-25

ドテシル硫酸ナトリウムと非イオン性高分子との水溶液中における結合熱

スポンサーリンク

概要

著者

関連論文

スポンサーリンク