Wrinkle-Engineered Parylene Thin Films for Optical and Security Applications

Poly(para-xylylene), commonly known as parylene, is widely utilized as a conformal coating material due to its excellent chemical stability, pinhole-free deposition, and superior barrier properties. Beyond its conventional role as a protective coating, parylene thin films can serve as functional platforms through controlled surface morphology engineering. In this presentation, wrinkle-engineered parylene thin films are introduced for optical and security applications.

Periodic wrinkle structures are generated through mechanical mismatch between parylene thin films and elastomeric substrates, producing tunable surface morphologies without complex lithographic processes. First, these wrinkle structures are employed as optical outcoupling layers for organic light-emitting diodes (OLEDs). The engineered microstructures enhance optical scattering and reduce total internal reflection, resulting in improved light extraction efficiency. Numerical simulations and device demonstrations confirm the effectiveness of wrinkle-induced optical modulation.

Second, the intrinsic randomness of wrinkle formation is exploited for physical unclonable functions (PUFs). Random surface morphologies generate unique optical signatures that can be converted into digital fingerprints for authentication and hardware security applications. The resulting PUF devices exhibit excellent uniqueness, reliability, and scalability.

These results demonstrate that wrinkle-engineered parylene thin films provide a simple, scalable, and multifunctional platform for next-generation optoelectronic and hardware security systems.