Weathering resistance of the function of an injection-moldable electrochromic multilayer film (BeSpECD)

• Applicant: Professor Dr.-Ing. Hans-Peter Heim
• Subject Area: Polymeric and Biogenic Materials and Derived Composites ; Plastics Engineering
• Term: since 2024
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 535405317

The aim of the proposed research project is to characterize the resistance to weathering of a flexible EC film with a specific layer structure that allows polycarbonate to be back-molded. The project builds on the aging investigations of the polymer electrolyte used in the previous project and is aimed at the overall system with the special layer structure. The weathering factors (influencing factors) to be considered are: Temperature, humidity, UV irradiation, time. The properties of the ECD to be considered (target values) are: Transmittance and color in the light and dark state, transmittance stroke, switching time and cycle stability. In addition, individual components such as half cells (working and counter electrodes) will be artificially weathered without and with electrolyte in order to investigate interactions and to better classify aging phenomena occurring in the ECD. The expected scientific findings are the differentiated description of the aging causes, mechanisms and phenomena in the ECD. Furthermore, by systematic variation of the influencing factors (statistical experimental design), the functional relationship between influencing and target variables will be described mathematically by means of a regression model and will allow the identification of interaction effects, i.e. the dependence of the effect of one influencing factor on another influencing factor. In addition, the new possibility of injection-compression molding is to be used to encapsulate part of the EC films with polycarbonate and thus to investigate the (protective) effect of this encapsulation on durability. A demonstrator will be used, which can be produced with existing mold inserts. Furthermore, UV absorbers are to be introduced into the capsule of some of the EC films overmolded in this way in order to investigate the effect on the resistance of the EC film to global radiation. The focus here is not on finding out that UV radiation can damage the organic components of the ECD or on investigating the protective effect of UV stabilizers, but on investigating the effect of the temperature increase of the ECD resulting from the irradiation.

• DFG Programme: Research Grants