Engineered Thermochromic Inks from Reversible to Irreversible Color Transitions for Dynamic Anticounterfeiting and
Yangyang Du1, Zipeng Qin1, Zuodong Zhang1
1State Key Laboratory of Heavy Oil Processing and Department of Biological and Energy Chemical Engineering, College of Chemical Engineering, China University of Petroleum (East China), 66 Changjiang West Road, Qingdao 266580, China.
Langmuir : the ACS Journal of Surfaces and Colloids
|August 15, 2025
Summary
Researchers developed dual-mode thermochromic inks using a microencapsulated ternary system. These inks offer reversible or irreversible color changes for applications in security, monitoring, and smart packaging.
Area of Science:
- Materials Science
- Chemical Engineering
- Nanotechnology
Background:
- Developing single thermochromic ink formulations with both reversible and irreversible color transitions presents significant challenges.
- Existing thermochromic materials often lack the durability and dual-mode functionality required for advanced applications.
- Tailoring color transitions for specific temperature ranges and environmental conditions remains an area of active research.
Purpose of the Study:
- To engineer dual-mode thermochromic inks capable of both reversible and irreversible color changes within a single formulation.
- To enhance the thermal stability and durability of thermochromic inks through microencapsulation.
- To explore the potential applications of these novel inks in areas such as anticounterfeiting, food monitoring, and smart packaging.
Main Methods:
- A microencapsulated ternary system was developed using 6'-(diethylamino)-1',3'-dimethylfluoran (DDF), bisphenol AF (BPAF), and 2-(4-benzoxyphenyl)ethyl decanoate (DPE).
- Reversible thermochromic properties were achieved via controlled lactone ring opening/closing mechanisms, with color differences quantified (ΔE*ab = 17.96-25.64).
- Irreversible variants were created by mixing reversible inks with pigments, and urea-formaldehyde shells were used for microencapsulation to improve thermal stability.
Main Results:
- The reversible thermochromic inks exhibited significant color changes (ΔE*ab = 17.96-25.64) driven by reversible lactone ring chemistry.
- Microencapsulation enhanced thermal stability and enabled solid-solid phase transitions, crucial for practical durability.
- Irreversible thermochromic inks were successfully developed, showing permanent color change at low temperatures without recovery.
- The inks demonstrated programmable logic operations (NOT, PASS1) and vivid two-color transitions on flexible substrates.
Conclusions:
- A universal method for designing multifunctional thermochromic materials with ultra-low-temperature responsiveness was established.
- The developed dual-mode thermochromic inks show great promise for tamper-proof anticounterfeiting, real-time frozen food monitoring, and smart packaging.
- This research bridges the gap between advanced security technologies and intelligent sensing systems through novel thermochromic material design.
