1. FP7-ICT-2013-10 Y Wei, Z Ahmed, R Torah and J Tudor Dispenser printed actively controlled thermochromic colour changing device on fabric for smart fabric applications Date:6 June 2016 University of Southampton CIMTEC 2016, Perugia, Italy

2. FP7-ICT-2013-10 Overview o EU CREATIF project o Chromism o Materials o Dispenser printing o Results o Conclusions

3. FP7-ICT-2013-10 CREATIF project o This research is funded within an EU project: CREATIF (www.creatif.ecs.soton.ac.uk) of which the target is to offer the creative and cultural industries state of the art printed smart fabrics and collaborative design software.www.creatif.ecs.soton.ac.uk o Smart fabric creative applications are: proximity sensing, electroluminescence, colour change and sound emission. o Demonstrating the fundamentals of a dispenser printing process to achieve thermochromic devices on fabric substrates.

4. FP7-ICT-2013-10 Thermo-chromism Chromism Changes in colour of a material brought by an external stimulus Photo- chromism Thermo- chromism Electro- chromism Mechano- chromism Other Chromisms

5. FP7-ICT-2013-10 Thermochromic materials Direct stimulus Structural properties (Physical) Indirect stimulus Chromophore (Chemical) Liquid crystals Leuco dyes

6. FP7-ICT-2013-10 Leuco Dyes o A wide range of colours available o A wide choice of activation temperatures o The colour changes over a range of temperature instead of a particular temperature o Can be easily formulated into a printable ink for textile applications

7. FP7-ICT-2013-10 Dispenser printing What is a dispenser printer? A dispenser printer is neither a 3D printer nor an inkjet printer Viscosity, Material types, Capability

8. FP7-ICT-2013-10 Active control thermochromic materials o The colour changing of a thermochromic material can be triggered passively or actively (electronically). o A printed resistive heater controls the colour changing process of the thermochromic device. o The temperature generated from the heater must match the activation temperature of the thermochromic material. o The thermochromic device can interact with other external sensors.

9. FP7-ICT-2013-10 Thermochromic device structure o Fabric: PVC coated polyester fabric o Thermochromic ink: activation starts from 31 o C o Conductive ink: cured at 125 o C o Drive current: 0.6A

10. FP7-ICT-2013-10 Dispenser printing and results Dispenser printing process Resistive heater Item to be displayed Thermochromic layer

11. FP7-ICT-2013-10 Heater design FEM evaluations 0.2 A 23.7 o C 0.4 A 26.5 o C 0.6 A 30 o C 0.8 A 36 o C 1.0 A 43 o C 1.2 A 52 o C 1.4 A 60 o C 1.6A 70 o C

12. FP7-ICT-2013-10 Heater design Thermal imaging evaluations 0.8 A 36 o C 1.0 A 40 o C 1.2 A 49 o C 1.4 A 58 o C 1.6 A 69 o C

13. FP7-ICT-2013-10 Thermochromic device OFF ON Dispenser printing and results (cont.)

14. FP7-ICT-2013-10 Conclusions o A printable thermochromic ink has been achieved with an activation temperature around 31 o C. o The printed thermochromic layer changes its colour from opaque black to translucent to review anything underneath. o The cured thermochromic and conductive layers are flexible.

15. FP7-ICT-2013-10 Thank you.