Vpliv temperature na kritično miceljno koncentracijo surfaktantov

diplomsko delo visokošolskega študijskega programa

Renata Novak (Author), Regina Fuchs-Godec (Mentor), Aljana Petek (Co-mentor)

Abstract

Namen diplomskega dela je bil določiti kritično micelarno koncentracijo (CMC) anionskega surfaktanta natrijev dodecil sulfat (SDS) in kationskega surfaktanta cetildimetilbenzilamonijev klorid (CDBACl) pri standardnih pogojih in proučiti vpliv temperature na vrednost CMC. Kot topilo smo uporabili Milli-Q vodo. Izbrano temperaturno območje je bilo med 283 K in 323 K. Meritve smo izvedli pri sedmih različnih temperaturah v prej omenjenem temperaturnem območju. Pri tem smo uporabili klasično konduktometrično metodo. Na osnovi grafične predstavitve, CMC v odvisnosti od temperature, smo v skladu z literaturo dobili krivuljo v obliki črke U, kar pomeni, da obstaja minimalna vrednost CMC za posamezni surfaktant pri določeni temperaturi. Na koncu smo izračunali še standardne termodinamske količine: stopnjo disociacije proti-iona (β), spremembo standardne entalpije micelizacije (〖ΔH〗_mic^°), spremembo standardne entropije micelizacije (〖ΔS〗_mic^°) in spremembo standardne proste Gibbsove energije (〖ΔG〗_mic^°). To smo naredili v skladu z dvema enačbama, ki se razlikujeta po tem, da ena vpliv temperature na stopnjo disociacije proti-iona β upošteva v celoti, druga pa ta vpliv na β zanemari. Stopnja disociacije proti-iona s temperaturo narašča. Ta ugotovitev velja za izbrano temperaturno območje in za oba izbrana surfaktanta. Standardna prosta Gibbsova energija micelizacijeje negativna (in glede na izbrano temperaturno območje skoraj konstantna), kar pove, da je proces micelizacije spontan proces.

Keywords

surfaktanti;kritična micelarna koncentracija;natrijev dodecil sulfat;standardna prosta Gibbsova energija;standardna entalpija micelizacije;standardna entropija micelizacije;stopnje disociacije proti-iona;

Data

Language:	Slovenian
Year of publishing:	2013
Typology:	2.11 - Undergraduate Thesis
Organization:	UM FKKT - Faculty of Chemistry and Chemical Engineering
Publisher:	[R. Novak]
UDC:	544.31:544.6.018.4(043.2)
COBISS:	17695510
Views:	1510
Downloads:	161
Average score:	0 (0 votes)
Metadata:

Other data

Secondary language:	English
Secondary title:	INFLUENCE OF THE TEMPERATURE ON THE CRITICAL MICELLE CONCENTRATION OF THE SURFACTANTS
Secondary abstract:	Purpose of this study was to determine the critical micelle concentration (CMC) of the anion surfactant named sodium dodecyl sulphate (SDS) and cationic surfactant cetyldimethylbenzilammonium chloride (CDBACl) under standard conditions. Moreover, the effect of the temperature on the CMC value was also investigated. The Milli-Q water was used as a solvent. Measurements were performed at different temperatures within the temperature range of 283 - 323 K. As measurement method the classical conductivity measurements were used. Using graphs CMC as a function of temperature are consistent with the literature given curve U-shaped, which means that there is a minimum value of the CMC for each surfactant at a given temperature. In the end the standard thermodynamic quantity: degree of counterion dissociation (β), standard enthalpy of micellization (〖ΔH〗_mic^°), standard entropy of micellization (〖ΔS〗_mic^°) and the standard Gibbs free energy (〖ΔG〗_mic^°) were calculated. This was done in accordance with the equations, which differ in that one the effect of temperature on the degree of counterion dissociation β takes into consideration as whole the other this effect ignores. It was found that degree of counterion dissociation increased with increasing temperature (within chosen temperature range) for both SDS and CDBACl. The values for standard Gibbs free energy are negative and almost constant within chosen temperature range, which indicates that the micellization process is spontaneous process for presented system.
Secondary keywords:	surfactants;critical micelle concentration;sodium dodecyl sulphate;standard Gibbs free energy;standard enthalpy of micellization;standard entropy of micellization;the degree of countrion dissociation;
URN:	URN:SI:UM:
Type (COBISS):	Undergraduate thesis
Thesis comment:	Univ. v Mariboru, Fak. za kemijo in kemijsko tehnologijo
Pages:	XII, 72 f.
ID:	8722321