Review accepted: “Patterns Matter - Part 1: Chitosan Polymers with Non-Random Patterns of Acetylation”

Today, part 1 of our review on the pattern of acetylation of partially acetylated chitosans has also been accepted for publication in the “Chitosan for the Future” Special Issue of the journal Reactive and Functional Polymers in honor and memory of George A. F. Roberts and Kjell A. Vårum. Patterns in polymers are even more challenging than in oligomers. We hardly know how to make them, we are only beginning to learn how to analyze them, and we are guessing rather than understanding what their significance may be, their influence on physico-chemical material properties and biological functionalities of chitosans. This is a question that has been investigated by both George and Kjell, with different results, and with no final answer yet. Both were interested whether chitosans produced by heterogeneous versus homogeneous deacetylation of chitin are similar or different in their patterns of acetylation (PA). George insisted that they are different because they behave differently in solution, but Kjell was able to show by 13C-diad analysis that both types of chitosans have random PA. George’s idea then was that the difference lies in the intermolecular dispersity of the fraction of acetylation rather in the intramolecular PA. To this day, this is an open question which we are trying to answer. But it requires that we first develop a technique to analyze this dispersity. We are working on it.