STUDI TERMODINAMIKA PEMBENTUKAN MISEL NATRIUM DODISEL SULFAT DALAM AIR MENGGUNAKAN MODEL AKSI-MASSA DAN TERMODINAMIKA SISTEM KECIL

Rahmawati, Fitria and Yahya, M. Utoro and Kuncaka, Agus (2001) STUDI TERMODINAMIKA PEMBENTUKAN MISEL NATRIUM DODISEL SULFAT DALAM AIR MENGGUNAKAN MODEL AKSI-MASSA DAN TERMODINAMIKA SISTEM KECIL. Teknosains, 14 (3). pp. 469-480.

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    Abstract

    Thermodynamics of micelle formation of aqueous solution of sodium dodecyl sulfate has been investigated by measuring the conductivity in various temperature of solution, hardness and pH of water, respectively. This thermodynamics study based on mass-action model and thermodynamics of small system. The determination of critial mmicelle concentration was dano by plotting the conductivity versus concentration of surfacant solution. Calculation of agregation number (n) were carried out using Huisman's empirical equation, the loarithmic of micellization constants (logKm) was calculated by modification of mass-action model by introducing the charge of monomer which form the micelle, the degree of counter ion assosiation () wascalculated using combination of Stoke law about viscosity of solution and Kohlrausch law for electrolyte solution, the number of free monomer (mf) was calculated using the differentation of Huisman's equation for concentration above CMC. The calculation of mf is an iteration technique using a computer program. The thermodynamic fuctions of micelle formation was calculated by mass-action model and thermodynamics of small system using computer program. The result of this research showed that the elevation of temperature will enhance critical micelle concentration, and at the relatively high temperature, above 313,15 K for SDS solution in aquadest, the critical micelle concentration is relatively constant. The hardness of water support the micelle formation, showed by the decreasing of CMC value in water-1 and water-2 from CMC value in aquadest, as the effect of hardness ions in water. Acid condition (pH=2) is very conducive for micelle formation, indicated by the samllest CMC for all water, the biggest log Km (micellization constant), and the most negative value of AGm0. The results of thermodynamic fuctions calculation indicated that micelle formation was caused mainly by condensation of hydrophobic groups as the result of induced-dipoles interaction between surfactant molecules. Keywords: micellization, sodium dodecyl sulfate, thermodynamics.

    Item Type: Article
    Subjects: Q Science > QD Chemistry
    Divisions: Fakultas Matematika dan Ilmu Pengetahuan Alam > Kimia
    Depositing User: mr azis r
    Date Deposited: 12 Jun 2013 21:50
    Last Modified: 12 Jun 2013 21:50
    URI: https://eprints.uns.ac.id/id/eprint/961

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