Bio-inspired crystal morphogenesis by hydrophilic polymers

Abstract

The latest advances in hydrophilic polymer controlled morphosynthesis and bio-inspired mineralization of various technically important inorganic crystals are reviewed with a focus on how to generate inorganic crystals with unusual structural specialty and complexity by double hydrophilic block copolymers (DHBCs). The systematic morphogenesis of different inorganic minerals with controlled morphology and novel superstructures by using DHBCs with varying patterns of functional groups will be described and influence of parameters such as crystallization sites, temperature, concentrations of reactants and copolymers, as well as cosolvents or the introduction of foreign colloidal structures on the morphology, crystallization, and superstructure will be discussed. We will demonstrate the ability of the copolymer to interact with inorganic crystals as well as the fine-tuning of morphosynthesis of inorganic crystals. Several different morphogenesis mechanisms are identified including selective polymer adsorption, mesoscopic transformations and higher order assembly. Mesoscopic transformation and formation of novel organic–inorganic superstructures by DHBC-mediated crystallization, combination of DHBCs with normal surfactants for the formation of new superstructures and the DHBC–crystal interaction will be reviewed as well as recent advances in the analysis of these systems and their formation mechanisms. Current developments emphasize that probably all inorganic crystals will be amenable to morphosynthetic control by use of either flexible molecular templates or suitable self-assembly mechanisms. Further exploration in these areas should provide new possibilities for the rational design of various kinds of inorganic materials with ideal hierarchy and controllable length scales. These unique hierarchical materials of structural specialty and complexity with a size range spanning from nanometers to micrometers are expected to find potential applications in various fields.