Evaluation by nitrogen adsorption of crystal aggregation in organic pigments

Organic pigments consist of tiny molecular crystals with a propensity to cl uster into aggregates. Such aggregation is commercially undesirable. The pr operties of the crystal aggregates can be investigated by the use of nitrog en adsorption isotherms. The review describes how a measure of the extent o f crystal aggregation can be provided from the combined application of nitr ogen isotherms and transmission electron microscopy. The application of ful l nitrogen isotherms to the study of crystal aggregation is also discussed. (C) 2000 Elsevier Science Ltd. All rights reserved.