四硅氧烷Gemini咪唑表面活性剂的合成及表面性能

以三甲基氯硅烷、 γ-氯丙基三氯硅烷、 1,4-二氯丁烷和咪唑等为原料合成了一种新型的四硅氧烷Gemini咪唑表面活性剂(Si₄-4-Si₄im]Cl₂), 通过质谱(MS)和核磁共振氢谱(¹H NMR)证明所得产物为目标产物. 通过Wilhelmy板法测得其在25 ℃下的临界胶束浓度(cmc)为0.54 mmol/L, 水溶液的表面张力(γ_cmc)降至18.6 mN/m. 通过电导率法研究了其胶束形成热力学参数(Δ\begin{array}{c}{G}_m^{0—}\end{array},Δ\begin{array}{c}{H}_m^{0—}\end{array}和Δ\begin{array}{c}{S}_m^{0—}\end{array}), 表明在15~35 ℃下其胶束化过程是自发进行的, 且为熵驱动过程.

Synthesis and Surface Properties of Siloxane Gemini Imidazolium Surfactant†

A new siloxane gemini imidazolium surfactant 3,3'-diγ-tri(trimethylsiloxy)silyl]propylchloride-1,1'-(1,4-butanediyl)-bisimidazole(Si₄-4-Si₄im]Cl₂) was synthesized with chlorotrimethylsilane, γ-chloropropyltrichlorosilane, 1,4-dichlorobutane and imidazole. The structure of the surfactant was characte-rized by MS and ¹H NMR spectra, and the results proved that it was consistent with the target structure. The surface tension of the surfactant was measured by Wilhelmy measuring plate method at 25 ℃. It indicates that the γ_cmc of the surfactant in aqueous solution can be reduced to 18.6 mN/m and the value of cmc is 0.54 mmol/L. The thermodynamic parameters of micellization(Δ\begin{array}{c}{G}_m^{0—}\end{array},Δ\begin{array}{c}{H}_m^{0—}\end{array},Δ\begin{array}{c}{S}_m^{0—}\end{array}) of the surfactant were researched by determination of the electrical conductivity in different concentrations. The results suggest that the process of micellization is spontaneous and micellization of Si₄-4-Si₄im]Cl₂ is entropydriven at 15—35 ℃.