A bio-inspired coating that mimics penguin feather function could help autonomous sensors see clearly when fog and rain would otherwise blur the signal.
Paper: Plasmonic nanocomposite helices for weather-adaptive LiDAR function. Image Credit: Giedriius / Shutterstock
In a recent study published in the journal Nature Communications, researchers developed a bio-inspired plasmonic nanocomposite coating that addresses scattering issues in light detection and ranging (LiDAR) systems. The coating is inspired by the water-repellent and thermoregulatory properties of penguin feather barbules, which combine light-absorbing melanosomes with hierarchical keratin structures.
The resulting bio-inspired plasmonic nanocomposite helix coating rapidly removes condensation, repels raindrops, and maintains high optical transparency at the LiDAR operating wavelength, offering a promising solution for reliable sensing under adverse weather conditions.
Designing a Nanostructure for All-Weather LiDAR Performance
Light detection and ranging (LiDAR) systems have become a cornerstone of autonomous vehicles, robotics, and outdoor sensing because they generate accurate three-dimensional maps of the surrounding environment. However, adverse weather continues to limit their performance. Microscopic fog droplets scatter laser beams, while larger raindrops refract and diffract light, weakening returned signals and reducing object detection accuracy.
Researchers have explored a variety of transparent photothermal coatings that convert sunlight into heat to remove surface condensation. Such coatings are usually made from graphene, carbon nanotubes, MXenes, or polymer-based materials. However, these materials also absorb near-infrared light, reducing transparency at the 905 nm LiDAR wavelength. Multilayer designs combine photothermal and hydrophobic functions but add complexity, increase optical losses, and raise production costs.
Researchers developed a multifunctional nanocoating that combines photothermal heating and water repellence. They embedded copper nanoparticles inside three-dimensional silica nanohelices to create plasmonic nanocomposite helices. The copper nanoparticles selectively absorb visible sunlight to generate heat while preserving high near-infrared transparency.
Optimizing the Bio-Inspired Nanostructure
The researchers combined computational modeling with experimental validation to optimize the nanocomposite coating. They first used finite-difference time-domain (FDTD) simulations to compare different plasmonic metals, oxide matrices, nanoparticle concentrations, film thicknesses, and nanostructure geometries. The simulations identified copper nanoparticles embedded in a silica matrix as the best combination for maximizing visible-light absorption while maintaining high transparency at the 905 nm LiDAR wavelength.
Based on the theoretical results, the team designed three-dimensional silica nanohelices with embedded copper nanoparticles and fabricated them using glancing-angle co-deposition. This approach produced highly porous nanostructures that minimized optical reflection while improving light transmission. They then applied a hydrophobic molecular coating to enhance water repellence.
Researchers characterized the nanostructures using electron microscopy, optical spectroscopy, contact-angle measurements, and photothermal testing. They also evaluated the coating through laboratory antifogging experiments, rainfall tests, outdoor sensing demonstrations, and mechanical durability assessments to verify its performance under realistic operating conditions.
Nanohelices Deliver High Transparency and Rapid Antifogging
The optimized plasmonic nanohelices combined selective photothermal heating with high optical transparency. Unlike conventional photothermal coatings, the nanostructure preserved more than 80% transmittance at the 905 nm LiDAR wavelength while efficiently absorbing visible sunlight. Under one-sun illumination, it raised the surface temperature by 9.3 °C, generating enough heat to remove condensed water droplets without an external power source.
The coating removed condensation within 6 seconds during outdoor LiDAR antifogging tests and restored full visible and near-infrared clarity within 6 minutes in controlled-chamber experiments. Its hierarchical nanohelical architecture also yielded a water contact angle of approximately 143°, allowing raindrops to bounce or roll off the surface rather than adhere. By combining photothermal heating with water repellence, the coating effectively removed both microscopic fog droplets and larger raindrops.
Outdoor experiments further demonstrated the coating's practical advantages. Under foggy conditions, the coated window recovered almost immediately after condensation formed, whereas bare glass required much longer to restore signal quality. During moderate rainfall, untreated glass showed about 20% signal decay after 20 minutes as water accumulated on the surface. In contrast, the plasmonic nanohelices maintained a stable LiDAR signal intensity by continuously repelling incoming droplets.
The researchers also evaluated the coating under conditions designed to simulate real-world use. High-pressure water, repeated mechanical rubbing, and sand abrasion revealed a geometry-dependent durability trade-off after applying an ultrathin alumina passivation layer. Two-turn nanohelices retained optical transparency, photothermal activity, and mechanically reinforced water repellence more effectively than higher-aspect-ratio three-turn structures, which showed partial damage under rubbing and sand impact, highlighting the platform’s potential for engineered long-term use in outdoor optical and sensing applications.
Shaping the Future of Multifunctional Nanocoating
This work highlights how bio-inspired nanotechnology can overcome a longstanding challenge in outdoor optical systems. Instead of combining separate photothermal and hydrophobic layers, the plasmonic nanocomposite helices integrate selective light absorption, efficient heat generation, and water repellence into a single engineered nanostructured coating. This multifunctional design minimizes optical losses while maintaining the high transparency required for advanced optical devices.
The developed technology has potential to support a wide range of outdoor applications beyond autonomous vehicles, including robotic vision systems, drones, surveillance cameras, environmental sensors, and smart windows. Future work should explore scale-up strategies, co-doping approaches, tailored spectral selectivity, longer infrared applications, and integration with curved lenses, LiDAR housings, and transparent displays.
Overall, the study introduces a versatile platform for multifunctional nanophotonic coatings. By combining bio-inspired design with plasmonic nanomaterials, the researchers have developed a practical solution that keeps optical surfaces clear under challenging weather conditions. The work demonstrates how nanoscale materials engineering can create smarter, more durable optical technologies for next-generation sensing, imaging, and photonic applications.
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