<scp>PDMS</scp>/Au/<scp>PDMS</scp> Multi‐Layered Thin Film Composites for Hydrophobic and <scp>IR</scp> Filtering Applications

ABSTRACT This study introduces a novel PDMS/Au/PDMS multi‐layered thin‐film composite designed for infrared (IR) filtering and hydrophobic coating applications, fabricated using spin coating and sputtering techniques. The composite, with an approximate thickness of 30 μm, exhibits a surface roughness that enhances near‐infrared (NIR) reflectance through diffuse scattering, achieving a reflectance of up to ~60%, while maintaining visible light transmission of approximately 70%. The choice of gold as the intermediate layer in this study is motivated by its optical property of surface plasmon resonance, which significantly contributes to the material's reflective characteristics in the NIR spectrum. This unique combination of NIR reflectivity and visible light transparency makes the film ideal for applications like solar cell encapsulation, with the potential to boost photon absorption while reducing heat buildup. Additionally, this composite film shows promise as a coating for greenhouse windows and for thermal management in electronic devices, representing a significant advancement in multifunctional, energy‐efficient materials.