Light scattering experiments of ctab micelle

Abstract

계면 활성제 CTAB의 광산란 실험을 수용액과 0.05 mole fraction의 DMSO와 물의 혼합 용매를 사용하여 25℃에서 행하였다. DMSO의 혼합용매에서 CTAB micelle이 CMC와 interaction constant는 증가하는 한편 분자량은 감소하였으며 Standard free energy도 감소하였다. 또 편극율 실험을 통하여 micelle의 isotropy를 측정한 결과 수용액에서보다 DMSO혼합 용매에서 percent isotropy가 증가함을 알 수 있다. 즉 DMSO혼합 용매에서 micelle을 형성하기가 어렵고 그 안정도도 약화된다고 할 수 있다. 이것으로 DMSO가 물분자와의 우세한 친화력 때문에 micelle형성에 원동력이 되는 hydrophobie force를 감소시킴으로써 micelle형성을 억제시키는 역할을 하는 것으로 사료된다.;The light scattering experiment of CTAB micelle in aqueous solution and DMSO-water mixture containing the mole fraction of DMSO, X_(DMSO)=0.05, are carried out with Aminco Absolute Light Scattering Photometer a t 25℃. As compared the results of DMSO mixture with those of aqueous solution, the CMC and interaction constant were increased, while molecular weight and standard free energy of micellization were decreased. Also isotropic character of CTAB micelle by observing the polarization ratio was increased in DMSO-water mixture. All of these indicate that the formation of micelle is more difficult in mixed solvent and the stability of micelle in DMSO mixture is weakened. Therefore it can be inferred that DMSO molecule interfered the formation of CTAB micelle since it has dominant affinity with the water molecule. This inhibitory effect can be explained in terms of decreased hydrophobic forces in micelle due to interactions between water and DMSO.