Noncontact Microfluidics of Highly Viscous Liquids for Accurate Self-Splitting and Pipetting.

Accurate dosing for various liquids, especially for highly viscous liquids, is fundamental in wide ranging from molecular crosslinking to material processing. Despite droppers or pipettes being widely used as pipetting devices, they are powerless for quantificationally splitting and dosing highly viscous liquids (> 100 mPa⋅s) like polymer liquids due to the intertwined macromolecular chains and strong cohesion energy. Here, we provide a highly transparent photopyroelectric slippery (PS) platform to achieve noncontact self-splitting for liquids with viscosity as high as 15000 mPa⋅s, just with the assistance of sunlight and a cooling source to provide a local temperature difference (ΔT). Moreover, to guarantee the accuracy for pipetting liquids (> 80%), the ultrathin MXene film (within a thickness of 20 nm) was self-assembled as the photo-thermal layers, overcoming the trade-off between transparency and photothermal property. Compared with traditional pipetting strategies (∼ 1.3% accuracy for pipetting polymer liquids), this accurate microfluidic chip shows a great potential in adhesive system (bonding strength, twice than using the droppers or pipettes). This article is protected by copyright. All rights reserved.