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本工作研究澳化十二烷基呲啶(C_(12)NBr)和硫酸十二烷基钠(NaC_(12)S)两种正、负离子表面活性剂的混合溶液(加入溴化钠作成等离子强度溶液)的表面吸附。用滴体积法测定C_(12)NBr水溶液、等离子强度的、不同C_(12)Br-NaC_(12)S比例的水溶液及1:1当量C_(12)NBr-NaC_(12)S混合溶液的表面张力。利用等离子强度条件下的Gibbs吸附公式 -((dγ/dln m_N))_m_S=RTГ′_N及- -((dγ/dln m_N))_m_N=RTГ′_S,可分剧求出正、负表面活性离子的吸附量。结果表明: 1.负离子表面活性剂之存在大为增加正离子表面活性剂的表面活性;反之亦然。1:1当量C_(12)NBr-NaC_(12)S混合溶液的CMC约为2×10~(-5)m,比C_(12)NBr溶液的CMC约小650倍。 2.负离子表面活性剂之存在促进正表面活性离子的表面吸附;反之亦然。这恰好与负、负表面活性离子混合溶液及丁醇-负表面活性离子混合溶液之情形相反。 3.加无机盐(NaBr)对1:1当量C_(12)NBr-NaC_(12)S混合溶液的表面张力几无影响,亦即对吸附无显著影响。由此提出,对于无盐时的1:1C_(12)NBr-NaC_(12)S混合溶液,Gibbs吸附公式应为 -dγ/RT=(Г′_N+Г′_S)dlnm_N(或s) 4.1:1 当量混合溶液表面吸附的最小分子面积为16(?)~2(加NaBr)及15(?)~2(未加 NaBr)。因此可能有多分子吸附层的形成。此外,自实验结果的解析提出1:1当量混合溶液的表面无双电层;而正、负表面活性剂的高表面活性及高吸附量的产生,是由于长链间的van der Waals引力及正、负离子的静电引力的作用。
In this work, a mixed solution of two kinds of positive and negative ionic surfactants, sodium dodecylpyridinium (C_ (12) NBr) and sodium dodecyl sulfate (NaC_ (12) S) Strength solution) surface adsorption. The droplet volumetric method was used to determine the aqueous solution of C 12 NBr aqueous solution with different ionic strength, different C 12 Br-NaC 12 S ratios and 1: 1 equivalent C 12 NBr-NaC 12 S mixed solution Surface Tension. Using the Gibbs adsorption equation - ((dγ / dln m_N)) _ m_S = RTГ’_N and - ((dγ / dln m_N)) _ m_N = RTГ’_S under the condition of plasma strength, positive and negative surface activity Ion adsorption capacity. The results show that: 1. The presence of anionic surfactant significantly increases the surface activity of the cationic surfactant; and vice versa. The CMC of 1: 1 equivalent C 12 NBr-NaC 12 S mixed solution is about 2 × 10 -5 m, which is about 650 times smaller than the CMC of C 12 NBr solution. 2. The presence of an anionic surfactant promotes surface adsorption of positive surface-activated ions; and vice versa. This happens to be the opposite of negative and negative surfactant mixed solutions and butanol-negative mixed surfactant solutions. Addition of inorganic salt (NaBr) has little effect on the surface tension of 1: 1 equivalent C 12 NBr-NaC 12 mixed solution, that is to say, it has no significant effect on the adsorption. It is suggested that Gibbs adsorption formula should be -dγ / RT = (Γ’_N + Γ’_S) dlnm_N (or s) 4.1 for 1: 1C_ (12) NBr-NaC_ (12) S mixed solution without salt : The minimum molecular area adsorbed on the surface of 1 equivalent mixed solution is 16 (?) ~ 2 (plus NaBr) and 15 (?) ~ 2 (without NaBr). It is therefore possible to have a multi-molecularly adsorbed layer. In addition, the results of the experimental results suggest that 1: 1 equivalent mixed solution surface without electric double layer; and positive and negative surfactants, high surface activity and high adsorption capacity, due to the long chain between the van der Waals attraction and positive , The role of negative ions electrostatic attraction.