Swift Droplet Manipulation on BTO/Polyimide Slippery Surfaces.

Droplet manipulation on functional surfaces is an urgent problem to be solved. Fast and precise droplet manipulation plays an important role in many applications, such as microreactors and microfluidics. Although numerous techniques have been developed to manipulate droplets by injecting external stimuli, it remains a challenge to achieve high-precision, high-sensitivity, and fast droplet manipulation on smart, slippery response surfaces. Here, we report an intelligent slippery photopyroelectric response near-infrared-induced MXene-barium titanate/polyimide (SFMBPI) membrane. By using local near-infrared radiation (NIR), we can precisely control the droplet transport on the SFMBPI membrane, and SFMBPI uses electrospinning technology to better lock the dimethylsilicone oil, reducing the loss during the control process. Moreover, due to the presence of the pyroelectric layer, double external stimuli can be achieved. The thermal stimulation of the photothermal layer and the charge action of the pyroelectric layer make the manipulation of droplets on the SFMBPI surface more efficient and faster. Moreover, the experiment of negative gravity transport at an inclination angle of 6° demonstrates that the existence of the pyroelectric layer results in a greater driving force on the droplets, which can be more widely used. In addition, by inducing the direction of the NIR, programmable droplet transport and droplet merging can be achieved. Also, the SFMBPI membrane can be used for underwater bubble manipulation. This precise manipulation of droplets on the surface of SFMBPI membranes can be widely used in other fields, such as microfluidics.