Large-Area 2D Colloidal Microchannel Formation Under Non-Equilibrium Condition

To face formidable challenges of future electronics with complex functionality and architecture, not only new materials but also new fabrication method need to be developed. However, topographical micropatterns (such as microchannels) are conventionally fabricated by complicated lithographic method, which are usually expensive and time-consuming, and not suitable for high throughput manufacture. Therefore, a low-cost, large-scale method for topographical template preparation needs to be developed. Recently, cracks formed in drying colloidal film have been demonstrated as ideal materials for microscale manufacturing. In this work, we first studied the key parameters that affect the dimensions of colloidal microchannel, such as channel-to-channel distance, channel width, and theoretical model is proposed to provide insights on colloidal microchannel formation. Then, the criteria for 2D microchannel formation (i.e., microchannel formed in both x and y direction) are investigated. The dimensions of 2D microchannel will be tuned by varying non-equilibrium condition, such as convective flux, temperature and evaporation rate. This work will provide a general strategy for generating of 2D microchannels, thereby offering a low-cost, large-area and lithography-free method for fabrication of patterns for printed electronics.