Materials that switch reversibly between two different colors or between colorless and colored states by an electrical voltage are called electrochromic materials.
The Fraunhofer IAP is increasingly involved in the production, modification and research of the electrolytes required for electrochromic cells, as well as the technology for processing into stable, sophisticated assemblies. The coloring substances used are primarily organic dyes and polymers.
The project was funded by the BMWi as part of the research initiative EnOB (energy-optimized construction).
Without costly vapor deposition technology and with organic polymers and dyes as colorants, an electrochromic casting resin for the production of actively switching, very stable glass composites was developed. This meets the high standards of conductivity, transparency and in particular the stability industries such as shipbuilding and architecture demand of such a glazing.
The project brought together existing technologies of cast resin composite glass and electrochromism. An all-in-one solution was created that allows simple laminated glass fabrication without using energy-consuming and time-consuming additional steps. Typical examples of this would be an upstream vapor deposition or sputtering, processes that use known electrochromic solutions. The developed casting resins can easily be integrated into existing industrial processing processes. By UV curing, they form stable cast resin composites, which are comparable in mechanical properties with existing non-electrochromic composites.
The casting resins developed in the project already contain the precursor of the electrochromic colorant as a monomer. After curing of the composite, these monomers are electrochemically polymerized on a TCO-coated glass. This process scales well.
TCO – transparent conducting oxide
Fraunhofer Institute for Applied Polymer Research