Molecular modelling is proving to be a useful tool in understanding the fundamental interactions between molecules and surfaces. With the use of the supercomputer at Australian National University (ANU) calculations on quite large molecules such as triglycerides and polymers can be made. The effect of the chemical structure of different fixatives on the interaction with the various components within pitch can be understood with the use of molecular modelling. Care is needed in choosing the most appropriate method to model the interactions. Geometry optimisation at the higher level of theory using quantum mechanics is needed. Comparison of different quantum mechanical methods yielded similar results indicating that the methods using the less computing power would be adequate in helping to gain a more fundamental understanding of the interactions that occur between various fixatives and pitch.