ABSTRACT
Petroleum asphaltenes are surrounded by myths and speculations basically due to the vast complexity of petroleum constituents and the numerous permutations of possible isomers. Hence this complicates the interpretation of experimental results and at worst blurs the final conclusions. This chapter gathers information related to the area of asphaltene association and aggregation, which over decades have been the prime object of scientific investigations. The association mechanism acts as a step toward either increased stability of the molecular structures involved or as a step toward phase separation. The phase separation is the main reason for the great interest paid to these materials in the petroleum industry through almost a century.
