Rapid prototyping of PET microfluidic chips by laser ablation and water‐soaking bonding method

Abstract

The solution to the commercialisation of polymer microfluidic chips lies in the chosen of a low-cost and concise method. CO₂ laser is an excellent tool for ablating arbitrary-shaped microchannels in most of thermoplastics. However, upheaval area is usually generates along the microchannel due to high temperature during laser ablation process which leads to the difficulty in fully bonding polymer microchannels. In this work, a new bonding method for fully bonding uneven substrates with homogenous surface property was developed based on water-soaking treatment. To prevent edge separating, an extra laser welding on the lateral of the chip was conducted. The influence of laser current on the width and depth of poly(ethylene terephthalate) (PET) microchannel was investigated. The mechanism of water-soaking bonding was explained and the parameters of this method were optimised. The experiments showed that PET chip can be fully bonded without any block or leakage and the bonding strength of PET chip can be as high as 3.4 MPa.