科研之友
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摘要
As regards microfluidic chips，the advancement of self-driven microfluidics is hindered by the limitations of microchannel and nanochannel fabrication techniques. Therefore，the fabrication of microchannels and nanochannels by using a diamond cutter wheel featuring serrated microtips to roll the surfaces of hard and brittle chip materials was proposed in this study. The mechanism of microchannel and nanochannel formation was analyzed through experimental studies，and the mechanisms of the process parameters and material properties，as well as the self-driven micro-rheological properties，were investigated. The results indicate that at a certain feed depth and the barometric pressure，stress concentration occurs on the material contact surface at the microtip of the cutter wheel. Once the crack penetration value between the indentations is reached，nanochannels are formed on the material surface at a speed significantly higher than the cutter wheel rolling speed，and microchannels are formed when the strength limit of the material is exceeded. The aspect ratio increases with the maximum stress. The maximum-stress ranges for nanochannel formation in 4H-SiC，sapphire，and optical glass are 266-750，256-600，and 74-150 MPa respectively，with optical glass exhibiting nanochannels with aspect ratios as high as 1. 1 and surface roughness values as low as 1 nm. Low-hardness materials can produce nanochannels with higher aspect ratios，while high-fracture toughness materials exhibit the highest surface quality. In addition，the self-driven microflu-ids in nanochannels can achieve flow velocities as high as 0. 055 mm/s and doses as low as 0. 001 μm3/s. ? 2023 Chinese Academy of Sciences.
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