カチオン性高分子電解質とアニオン性界面活性剤からなる高分子－界面活性剤複合体単分子膜の摩擦·摩耗挙動

摘要

Monolayers were prepared from a polymer-surfactant complex(PSC)with a cationic polyelectrolyte,poly(dimethyldiallylammonium chloride)(PDMDAAC),and anionic surfactants,sodium dodecyl sulfate(SHS)or hexadecanoic acid(C16A).The monolayers were characterized by surface pressure(π)-area(A)isotherms,Brewster angle microscopy(BAM)and X-ray photoelectron spectroscopy(XPS).The PSC monolayers were deposited onto glass substrates with the Langmuir-Blodgett technique and their tribological behavior was evaluated.Friction coefficients for PSC-covered substrates were 0.04-0.07,which was similar to those for substrates covered by low-molecular C16A or neutral poly(hexadecyl acrylate)(PHDA).When PSC-covered substrates were scratched with stainless bars,they began to wear after 734 laps for SHS/PDMDAAC films and 1057 laps for C16A/PDMDAAC films,which were superior to those of C16A films(67 laps)and PHDA films(331 laps).%カチオン性高分子電解質であるポリジメチルジアリルアンモニウムクロリド(PDMDAAC)とアニオン性界面活性剤がイオン結合を介して結合した高分子－界面活性剤複合体(PSC)で単分子膜を調製し，この単分子膜の特徴を表面圧－面積等温線測定，ブルースター角顕微鏡(BAM)観察ならびにX線光電子分光法(XPS)で明らかにした．また，これらのPSC単分子膜で被覆したガラス基板の摩擦·摩耗挙動を測定した．PSC膜で被覆した基板は，低分子化合物や電荷をもたない高分子の単分子膜で被覆した基板を比較すると，疎水鎖が同じ場合には摩擦係数は0.04-0.07と同程度であったが，ステンレスボール圧子を往復運動させたときの摩耗開始回数は，パルミチン酸膜の67回，アクリル酸オクタデシルの331回からSHS/PDMDAAC膜で734回，C16A/PDMDAAC膜で1057回と飛躍的に向上した．