用溴离子电极测定DTAB的CMC及反离子缔合度

Determination of critical micelle concentration and counter-ion association degree of aqueous dodecyltrimethylammonium bromide solution by bromide ion selective electrode

用溴离子选择性电极同时测定了阳离子表面活性剂十二烷基三甲基溴化铵(DTAB)水溶液体系中胶束的临界胶束浓度(CMC),及其反离子缔合度(K).测定结果表明:采用溴离子选择性电极方法和电导法分别测定得到的DTAB水溶液体系胶束的CMC值基本一致;但是,对于K的测定,采用溴离子选择性电极方法所得结果更符合胶束电化学理论所得K值,与电导法结果相比较,离子选择性电极方法具有灵敏度高、电极响应快、所需试样量少、方便快捷、数据准确可靠等优点,所得结果令人较满意.

Both critical micelle concentration(CMC) and the counter ion association degree (K) of aqueous dodecyltrimethylammonium bromide (DTAB) solution systems have been simultaneously determined by bromide ISE. The experimental results show that the CMC values of DTAB solution which are measured by bromide ISE and conductance are almost the same, but the K value obtained by ISE is in a quite good agreement with the electrochemical micelle theory. Comparing with conductance, ISE has many merits such as high sensitivity, quick electrode response, less sample, and it is both simple and quick. Further more, the results are accurate, reliable and satisfied.