Self-Assembly of Nanoparticles

In the process of seemingly random thermal motion, inorganic nanoparticles self-organize into variety of complex architectures.  Experimental data from this and other research groups indicate a general trend that self-assembly of nanoscale inorganic ‘building blocks’ occurs under a wider range of conditions than self-assembly of the similarly sized units from organic matter.  Simple water-soluble nanoparticles from metallic, semiconductor, or ceramic materials can form an immense variety of terminal assemblies, exemplified by supraparticles, nanoshells, virus-like assemblies, etc.  They are formed by 50-300 individual particles and, in many ways, similar to micelles or vesicles.   Slight but controllable variations of nanoparticle chemistry lead to extended assemblies, exemplified by chains, nanowires, sheets, ribbons, superlattices, etc. Their dimensions are not limited and when needed they can reach macroscale.  Remarkably, the internal organization of many of these terminal and extended assemblies rival in complexity to those found in biology. The amplified effects of subtle nanoscale anisotropy, collective behavior of nanoscale colloids, and non-additivity of their interactions contribute to their biomimetic behavior. 

In our ongoing studies, we are addressing the following questions:

  • (a) What are the limits of structural complexity and functions for nanoparticle superstructures?
  • (b) What are the intermolecular forces essential for nanoparticle interactions?
  • (c) What are the technological benefits of nanoparticle self-organization?

 

Building complex multiparticle systems is faster and simpler than putting them together one-by-one, which represents the practicality of self-assembly processes.  Their use of ‘free’ thermal energy to create complex functional systems makes them technologically attractive. Self-assembly of inorganic nanoparticles is utilized now for engineering of energy storage materials, biosensing protocols, and optolelectronic devices.