A Biocompatible Infrared Rewritable Technique Based on Flexible Conjugated Polymer PEDOT:DSS

Abstract With the rapid advancement of information technology, information security has become a major challenge in contemporary society. Optical cryptography has gained attention as a key research area in cryptography due to its unique multi‐dimensional storage and large‐capacity features. In this study, a novel infrared rewritable PEDOT:DSS film (IRR‐PDF) is introduced, that demonstrates excellent biocompatibility and flexibility. Furthermore, it can efficiently regulate thermal emission through a simple redox treatment and can be written and erased reversibly. Additionally, the operational principles of IRR‐PDF in modulating infrared thermal imaging are explored. This investigation reveals that the core mechanisms behind the phenomenon involve the modulation of polar transport properties of PEDOT molecules by redox agents and the regulation of infrared emission through changes in crystal conformation during the redox process. The discovery opens up new possibilities for practical applications in infrared direct writing and cryptographic encryption. The biocompatibility of PEDOT:DSS, which distinguishes it from other conductive polymers such as poly(3,4‐ethylenedioxythiophene):(styrenesulfonate) (PEDOT:PSS), allows IRR‐PDF to be widely used in smart wearables field. It also establishes a crucial technological link with the multi‐dimensional storage and high‐capacity features of optical cryptography, which provides novel insights and material foundations for future applications and advancements in information security.