Light-Induced Charged Slippery Surfaces

Light-induced charged slippery surfaces (LICS), which regenerate charge when illuminated, have the potential to pave the way for next-generation interfacial materials and microfluidics. A copolymer, tiny liquid metal particles, and lubricant-trapping microstructures make up the new material. It has the potential to be used in lab-on-a-chip devices, biological diagnostics, and chemical analysis.

Slippery lubricant-infused porous surfaces (SLIPS) hold great promise for self-cleaning, anti-icing, and anti-fouling devices that can withstand “fouling” by microorganisms that would otherwise accumulate on structures such as boat hulls or microfluidic chips. However, such lubricants have a disadvantage. They serve as a physical screen for the material beneath them, masking any desirable properties (such as surface charge). Such screening is ineffective in applications where droplets and liquids must be manipulated and transported across a slippery surface in a controlled manner.

Researchers have now created a slippery material resistant to these screening effects. The new light-induced charged slippery surfaces consist of three main components:

  • Micro-sized Ga-In liquid metal particles for efficiently converting absorbed light into local heat
  • Poly (vinylidene fluoride-co-trifluoroethylene) copolymer for its excellent ferroelectric behavior
  • Microstructures coated with a layer of hydrophobized SiO2 nanoparticles for lubricant trapping

The light-induced charged slippery surfaces could help build steerable droplet-based robots and perform chemical reactions. They could also be incorporated into a pump-free microfluidic chip, enabling reliable biological diagnosis and analysis in a closed design.

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