The interaction between N, N′-bis（dimethyldodecyl）-1,6-hexanediammoniumdibromide （G12-6-12） and cetyltrimethylammonium bromide （CTAB） in D20 aqueous medium has been investigated by NMR at 298 K. The G12-6-12 an...The interaction between N, N′-bis（dimethyldodecyl）-1,6-hexanediammoniumdibromide （G12-6-12） and cetyltrimethylammonium bromide （CTAB） in D20 aqueous medium has been investigated by NMR at 298 K. The G12-6-12 and CTAB are about 0.773 and measured critical micelle concentration （cmc） of 0.668 mmol/L, respectively. The cmc^＊ （cmc of mixture） values are less than CMC^＊ （cmc of ideally mixed solution） in the mixed system, and the interaction parameter βM〈0 at different molar fractions α of G12-6-12 in the mixed systems, but just when α≤0.3, cmc^＊ values are much smaller than CMC^＊, and βM satisfies the relation of ｜βM｜〉｜ln（cmc1/cmc2）｜ （cmcl： cmc of pure G12-6-12 and cmc2： cmc Of pure CTAB）. The results indicate that there exists synergism between G12-6-12 and CTAB, and they can form mixed micelles, which is further proven by 2D NOESY and self-diffusion coefficient D experiments. There are intermolecular cross peaks between G12-6-12 and CTAB in 2D NOESY, and the radius of micelles in mixed solution is bigger than that in G12-6-12 pure solution in D experiments, indicating there are mixed micelles. However, when α〉0.3, we find that cmc^＊≈CMC^＊, βM≈0, obviously, the two surfactants are almost ideal mixing fitting the pseudo-phase separation model and regular solution theory.展开更多
We explore the tricritical points and the critical lines of both Blume Emery Griffiths and Ising model within long-range interactions in the microcanonical ensemble.For K = Kmtp,the tricritical exponents take the val...We explore the tricritical points and the critical lines of both Blume Emery Griffiths and Ising model within long-range interactions in the microcanonical ensemble.For K = Kmtp,the tricritical exponents take the valuesβ = 1/4,1 =γ^-≠γ^+ = 1/2 and 0 =α^-≠α^+ =-1/2,which disagree with classical(mean ffeld) values.When K > Kmtp,the phase transition becomes second order and the critical exponents have classical values except close to the canonical tricritical parameters(Kctp),where the values of the critical expoents become β = 1/2,1 = γ^-≠γ^+= 2and 0 =α^-≠α^+ = 1.展开更多
文摘The interaction between N, N′-bis（dimethyldodecyl）-1,6-hexanediammoniumdibromide （G12-6-12） and cetyltrimethylammonium bromide （CTAB） in D20 aqueous medium has been investigated by NMR at 298 K. The G12-6-12 and CTAB are about 0.773 and measured critical micelle concentration （cmc） of 0.668 mmol/L, respectively. The cmc^＊ （cmc of mixture） values are less than CMC^＊ （cmc of ideally mixed solution） in the mixed system, and the interaction parameter βM〈0 at different molar fractions α of G12-6-12 in the mixed systems, but just when α≤0.3, cmc^＊ values are much smaller than CMC^＊, and βM satisfies the relation of ｜βM｜〉｜ln（cmc1/cmc2）｜ （cmcl： cmc of pure G12-6-12 and cmc2： cmc Of pure CTAB）. The results indicate that there exists synergism between G12-6-12 and CTAB, and they can form mixed micelles, which is further proven by 2D NOESY and self-diffusion coefficient D experiments. There are intermolecular cross peaks between G12-6-12 and CTAB in 2D NOESY, and the radius of micelles in mixed solution is bigger than that in G12-6-12 pure solution in D experiments, indicating there are mixed micelles. However, when α〉0.3, we find that cmc^＊≈CMC^＊, βM≈0, obviously, the two surfactants are almost ideal mixing fitting the pseudo-phase separation model and regular solution theory.
基金Supported by the National Natural Science Foundation of China under Grant No.11104032
文摘We explore the tricritical points and the critical lines of both Blume Emery Griffiths and Ising model within long-range interactions in the microcanonical ensemble.For K = Kmtp,the tricritical exponents take the valuesβ = 1/4,1 =γ^-≠γ^+ = 1/2 and 0 =α^-≠α^+ =-1/2,which disagree with classical(mean ffeld) values.When K > Kmtp,the phase transition becomes second order and the critical exponents have classical values except close to the canonical tricritical parameters(Kctp),where the values of the critical expoents become β = 1/2,1 = γ^-≠γ^+= 2and 0 =α^-≠α^+ = 1.
