LINCSAT: Toner-Assisted Laser-Induced NanoCarbon Synthesis and Transfer for Programmable Interfacial Wetting on Planar and 3D Substrates

Direct, ambient deposition of functional nanocarbon coatings remains challenging, particularly on low-service-temperature polymers and complex 3D substrates that cannot be directly laser-carbonized. Here we introduce Laser-Induced NanoCarbon Synthesis and Transfer (LINCSAT), a one-step process that couples laser carbonization of a polyimide donor with vertical transfer of nanocarbon to a physically separated receiver. A printed toner interlayer enhances optical absorption on the donor, enabling uniform coatings with thickness up to ≈ 44 μ m in a single pass at laser powers as low as ≈ 3 . 5 W. By systematically varying laser fluence and donor–receiver spacing (1–5 mm), we control coating thickness, morphology, and resulting wetting behavior. Raman spectroscopy, X-ray photoelectron spectroscopy, and electron microscopy confirm sp 2 -enriched nanocarbon with porous morphology and graphene interlayer spacing of 3.35 Å. On polypropylene, LINCSAT produces superhydrophobic surfaces (static contact angle ≈ 15 6 ∘ , roll-off ≤ 5 ∘ ) demonstrating the potential for self-cleaning surfaces, while on glass it yields parahydrophobic behavior with strong droplet pinning (hysteresis ≥ 8 0 ∘ ), enabling droplet immobilization for localized assays. The coatings exhibit good adhesion and structural stability, retaining morphology and wetting behavior after vortex-induced mechanical agitation at 2700 rpm. Conformal coatings are also achieved on 3D polypropylene sutures without thermal damage, demonstrating compatibility with complex geometries. Reproducible coating characteristics are observed across processing conditions with low variability across measurements (minimal standard deviations). Overall, LINCSAT provides a low-power, ambient route for conformal nanocarbon coating on planar and 3D substrates, extending laser carbon processing from in situ patterning to programmable interfacial functionality.