Soft matter in nature

Abstract

Abstract Until quite recently almost all the examples of soft matter that were of economic or practical importance were derived from living things. Foodstuffs, for example, are typically systems of colloidal or polymeric character, whose transformations by cooking processes are often best understood in terms of concepts such as those discussed in this book. Materials such as glues and paints were derived from natural products by simple processing techniques carried out on a craft scale; later industrial-scale processes, some still used, extensively modify natural polymers to produce products with less obvious relation to their natural origins. Examples include the modification of cellulose from tree pulp to produce cellophane sheets and rayon fibres, and the use of animal bones and skin to produce gelatin, which apart from its food use is still the main vehicle for photographic emulsions. In the early days of colloid science and polymer science many of the objects of study were essentially biological in origin. The second half of the twentieth century saw an increasing divergence between polymer and colloid science, on the one hand, and biology on the other. The invention of synthetic polymers and the massive growth of the plastics industry were accompanied by a parallel growth of polymer physics as a subject focused on synthetic rather than natural polymers, while the discovery of the genetic code and the development of protein crystallography led to a new discipline of molecular biology, whose research prograrnrne, pursued with spectacular success and intellectual confidence, concerned itself with rather different issues.