Microchannels Machining And Ship's Ballast Water Detection On A PMMA Microfluidic Chip

On the basis of microchannels,the microfluidic chips have extensive application in chemical detection,biological analysis,medical engineering and so on.The present methods of fabricating microchannels mostly are expensive and difficult for large-scale manufacturing.Therefore,PMMA is chosen to be the material for microchannels because of its low cost,easily fabrication and chemical properties.In the thesis,PMMA microchannels are machined by CO2 laser.It is analyzed that the impacts on PMMA channels' microstructure from different parameters in laser engraving and PMMA microchannels are selected to obtain narrow microchannels.A PMMA microchannel clamp has been designed and manufactured to achieve the compression of PMMA microchannels vertically in the oven where the temperature is higher than the glass transition temperature.Through the experiment method,it has been studied that the microchannel width changes under different temperature distribution,clamp pressure and the PMMA microchannel position relative to the compression surface in order to obtain the narrow PMMA microchannels.Meanwhile,PMMA compression in the clamp has been simulated by ANSYS to demonstrate the deformation distribution and the PMMA microchannel width changes.Thermal bonding is adopted to make a complete PMMA chip,which PMMA with microchannels is thermal bonded to the other PMMA piece under compression at a certain temperature.The dry and wetted PMMA chips have been stored for different time intervals to find the changes in wettability and channel width of PMMA chips,laying the foundation of PMMA chips' green application in market.Focusing on ship's ballast water algae detection,based on the microchannel compression and the previous detecting technology via polymer microfluidic chips,through the thermal bonding and clamp compression,PMMA microfluidic chips were employed for counting detection of algae in ship's ballast water on the basis of RPS principle.The RPS detecting channel has been utilized to size and count the algae.Chlorella,Platymonas subcordiformis and Prorocentrum micans are chosen to be the target samples on behalf of ballast water.A Labview program is used to detect and collect the signals of algae particles when a target particle passing through the detecting area.It has been proved that the PMMA chip is able to detect the algae particles effectively and constantly with appropriate signals.