Laser assisted microfluidic membrane evaporator for sample crystallization separation

Microfluidic devices for sample crystallization separation plays crucially important role in various on-chip analytical and testing scenes. Evaporation-based microfluidic crystallization technology is one of the most important methods for on-chip sample enrichment and crystallization separation. However, the solvent evaporation process in closed chip device is severely limited by poor vapor transportation, unstable interfacial behaviors and low evaporation rate. Aiming to address these issues, here we designed a microfluidic membrane evaporator for fast continuous flow sample crystallization separation. In this design, laser induced heating effect was employed to trigger the evaporation of the solvent, gas-permeable hydrophobic polytetrafluoroethylene membrane was used to stabilize the gas-liquid interface and provide vapor pathways during the evaporation process. Effects of laser power, solution flow rate and sample concentration on the crystallization separation performance was investigated. Results indicates the designed microfluidic membrane evaporator has good crystallization separation performance under different operation conditions, which can be further applied to different types of microfluidic systems and platforms for on-chip analysis and testing.