Calorimetric and physico-chemical study of sulfobetaines micellization in the presence and the absence of polystyrene nanoparticles.
نویسندگان
1 Laboratory of Physical chemistry of macromolecules and biological interfaces, Mustapha Stambouli university, Mascara, 29000, Algeria
2 Laboratory of Physical chemistry of macromolecules and biological interfaces, Mustapha Stambouli university, Mascara, 29000, Algeria
3 Laboratory of Physical chemistry of macromolecules and biological interfaces, Mustapha Stambouli university, Mascara, 29000, Algeria
4 Laboratory of Physical chemistry of macromolecules and biological interfaces, Mustapha Stambouli university, Mascara, 29000, Algeria
5 Laboratory of Physical chemistry of macromolecules and biological interfaces, Mustapha Stambouli university, Mascara, 29000, Algeria
6 Laboratory of Physical chemistry of macromolecules and biological interfaces, Mustapha Stambouli university, Mascara, 29000, Algeria
7 Mascara University, Algeria
doi
10.22034/crl.2025.497364.1517چکیده
This work investigates thermodynamic and physico-chemical properties of two zwitterionic surfactants (n-alkyl-N, N-dimethyl-3-ammoniopropanesulfonate, SB3-12 and SB3-14) in the presence and absence of polystyrene nanoparticles PS-NPs. The micellization process in water was studied using isothermal titration calorimetry (ITC) and dynamic light scattering (DLS) in the temperature range from 293.15 K to 323.15 K as well as by tensiometry at 298.15 K. For pure surfactant solutions, the increase in both temperature and the alkyl chain length leads to more negative values of Gibbs free energy of micellization (ΔG°mic), favoring the micellization. From the temperature dependence of micellization enthalpy (ΔH°mic), the values of micellization heat capacity changes (ΔC°p, mic) were found negative for the two surfactants relating to the removal of water accessible non-polar surfaces. DLS measurements showed that micelles aggregates size Dh are around 5.5 nm and 6.5 nm for SB3-12 and SB3-14 respectively with a pronounced hydrophobic effect as confirmed from tensiometry experiments. Furthermore, the aggregation numbers Nagg of SB3-12 and SB3-14 micelles were determined from isothermal titration calorimetry for the first time. The deduced values were in agreement with (DLS) results at high temperatures. In the presence of polystyrene nanoparticles (PS-NPs), the formation of micellar aggregates occurs by association between PS-NPs and surfactants at low concentration of surfactants as revealed from ITC and DLS analysis. These results suggest that the PS-NPs/surfactant association is based on hydrophobic interactions.
