Self-assembly of (sub-)micron particles into supermaterials

Abstract

We review aspects of static self-assembly with regard to the synthesizing of new types of three-dimensional materials made of specifically designed particles in the 100 nm to 10 µm range. Mechanical interconnection technologies based on static friction used in the assembly of macroscopic systems (such as screws and nails) are unsuitable for self-assembly. An analogy of self-assembly with first-order phase transitions is used to argue that self-assembly is a process requiring interfaces separating assembled and disordered regions. Available types of interaction are reviewed with emphasis on scaling. We discuss at some length how interaction and dynamic properties scale with respect to the particle size. Chains of particles seem to be of particular importance as they might form three-dimensional structures similar to proteins. These structures are constrained by the sequence of the particles and by their interactions between themselves and with the solvent. Using chains might provide a viable route to complex, inhomogeneous, supermaterials and systems. Kinetic processes, specifically nucleation and the relationship between self-assembly and thermodynamic phase transitions form a major part of this paper. Finally we review some applications of self-assembly, notably in MEMS, and put forward some ideas for the assembly of new types of (smart) supermaterials with interesting optical, mechanical, electrical and magnetic properties and describe some of the technological challenges we face when attempting to realize these materials and systems thereof.