Majda Krajnc

The Role of Intermolecular Interactions in the Micellization Process of Alkyltrimethyl Ammonium Bromides in Water

Abstract The micellization process of model cationic surfactants, alkyltrimethylammonium bromides with different alkyl chain length: dodecyl-(C12TAB), tetradecyl-(C14TAB) and hexadecyl- (C16TAB) has been investigated by the conductivity measurements over the temperature range 298.2 K–313.2 K. Understanding micelle formation requires its complete thermodynamic parameters, which were estimated by applying the proposed alternative derivation of pseudo-phase model. The critical micelle concentration (CMC), standard free Gibbs energy (ΔmicG0), enthalpy (ΔmicH0) and entropy (ΔmicS0) of micellization were analysed as a function of the increase in alkyl chain and temperature. At lower temperatures, the micellization in each case was found to be entropy-driven due to the increase in bulk water entropy. London or dispersion interactions are responsible for the cohesion between the apolar chains in the micelles and increase as the length of chains increases. ΔmicH0 reflects the contribution of London interactions, electrostatic repulsion between head groups and removing the alkyl chains from water (dehydration of CH2 and CH3 groups). As the temperature is increased, less energy is required for dehydration and hence the enthalpy of micellization became more exothermic and its effect more significant. The enthalpy-entropy compensation phenomenon was observed for all studied surfactants.

Teachers’ sense of efficacy in their work with pupils with learning, emotional and behavioural difficulties

ABSTRACT This study investigates primary school teachers’ sense of efficacy in their work with pupils with learning, emotional, and behavioural difficulties (LEBD), both in mainstream inclusive classrooms and in special classrooms for pupils in residential treatment institutions. Using an online questionnaire survey, data were collected on teachers’ self-efficacy, efficacy beliefs on their ability to teach LEBD pupils, and perceived ability to apply knowledge from different socio-pedagogical areas. Mainstream classroom teachers perceived higher efficacy in collaborating with parents of LEBD pupils, in most aspects of their ability to handle pupils’ learning and behavioural problems, and in most aspects of their ability to use knowledge from different socio-pedagogical areas. Conversely, special classroom teachers perceived higher efficacy in aspects related to their pupils’ engagement and comprehension of learning material, and in their classroom management ability, particularly in managing pupils’ disruptive behaviour.