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Encoding and Encryption via Dual-Wavelength 3D Digital Light Processing
Finn Kröger1,2, Michał P Świątek1,2, Eva Blasco1,2
1Institute for Molecular Systems Engineering and Advanced Materials, Heidelberg University, Heidelberg, Germany.
Angewandte Chemie (International Ed. in English)
|July 17, 2026
Summary
Researchers developed 3D-printable materials that store and encrypt information using light and pH changes. This innovation advances multi-responsive materials for data storage and security applications.
Area of Science:
- Materials Science
- Chemistry
- Engineering
Background:
- Additive manufacturing enables novel material functionalities.
- Multi-responsive materials offer advanced applications in data storage, security, and sensing.
- Integrating photo- and pH-responsive elements is key for complex functionalities.
Purpose of the Study:
- To create 3D-printable complex structures for information encoding and encryption.
- To combine photo- and pH-responsive chromophores in a single ink formulation.
- To demonstrate reversible information encryption using pH variation.
Main Methods:
- Utilized a multi-wavelength digital light processing (DLP) system for 3D fabrication.
- Employed 405 nm LED for photopolymerization and 365 nm LED for spiropyran isomerization.
- Incorporated spiropyran (photo-responsive) and phenolphthalein (pH-responsive) derivatives.
Main Results:
- Successfully fabricated initially colorless 3D structures.
- Achieved layer-by-layer information encoding via spiropyran isomerization.
- Demonstrated reversible encryption and decryption of encoded information using pH changes.
- Phenolphthalein enabled modulation of optical contrast for temporary unreadability.
Conclusions:
- Additive manufacturing of multi-responsive materials enables complex 3D information storage and encryption.
- The developed system allows for on-demand, reversible encryption of encoded data.
- This research opens new avenues for engineering multi-responsive functionalities in 3D architectures.

