Research

The formation mechanism of ordered colloidal particles self-assembly and the applications

The large and high quality colloidal crystals play an increasingly important role in the templating of photonic crystals, optical switching, drug delivery and biosensors. Here we show the fabrication of the highly ordered colloidal particle assembling by precisely controlling the concentration field. The technology is identified under a completely new understanding of the nucleation mechanism of colloidal self assembly, which allows a better control of the perfection of crystals based on a well-defined driving force.

Objectives:

· To obtain in depth understandings of the kinetics of colloidal particle self-assembly.
· To identify the novel technology to control colloidal crystallization for the various applications.
· To explore the technologies in fabricating photonic crystals, optical switching, drug delivery and biosensors.

Key approaches:

· New technologies are utilized to control the concentration and supersaturation gradient of suspended colloidal particles.
· Some important parameters of kinetics of colloidal self-assembly are measured through the statistics of the cluster distribution.
· The number of ordered colloidal domains can be controlled by carefully selecting the supersaturation. The optimum parameters to grow the colloidal crystals of a high degree of perfection can be obtained.

Fig.1 The correlation between the creation rate of colloidal particle self-assembly and the thermodynamic driving force. Based on this result, the optimal condition for the fabrication of high quality colloidal crystals can be identified.

 

Fig. 2 (a) The suspended colloidal particles; (b) Multi domain ordered colloidal assembly formed under a directional concentration field; (c) A large high quality colloidal crystal formed under the optimal colloidal crystallization condition; (d) A photonic crystal fabricated using the colloidal crystal as a template.