TY - JOUR
T1 - Routes towards manufacturing biodegradable electronics with polycaprolactone (PCL) via direct light writing and electroless plating
AU - Abdulrhman, Mansour
AU - Zhakeyev, Adilet
AU - Fernández-Posada, Carmen M.
AU - Melchels, Ferry P. W.
AU - Marques-Hueso, Jose
N1 - Funding Information:
M A and J M H acknowledge the Libyan Embassy in UK for support under the Grant Ref. 13691. A Z and J M H thank the UK EPSRC for support (EP/T013680/1). We wish to acknowledge the support of the Henry Royce Institute for advanced materials through the Researcher Equipment Access Scheme enabling access to XPS facilities at Cambridge (EPSRC, EP/R00661X/1).
Publisher Copyright:
© 2022 The Author(s). Published by IOP Publishing Ltd.
PY - 2022/6
Y1 - 2022/6
N2 - The electronic industry has room for improvement in adopting cleaner strategies, both in production processes (often energy-intensive and polluting) and in waste management. Many small components like security tags are routinely disposed of via general waste, which could be reduced adopting biodegradable polymers. In this work, a method for selective deposition of metallic micro-tracks on polycaprolactone (PCL) for circuitry integration is presented. The polymer is biodegradable, flexible, suitable for 3D printing, and can be obtained from sustainable sources. Photoreduction of Ag ions was used to generate seeds for subsequent selective electroless copper (Cu) plating in a process that avoids common but undesirable compounds such as cyanides and palladium. Two different photopatterning methods were successfully used to achieve selective Cu plating: flood exposure with a 460 nm light-emitting diode (LED) and direct laser writing (DLW) using a 405 nm laser, achieving 47 ± 11 μm wide tracks. The deposition of uniform Cu layers on PCL substrates is demonstrated, with thicknesses of up to 14 μm and electrical conductivities of up to 2.06 × 107 S m-1, which is near the conductivity of bulk Cu (5.89 × 107 S m-1). Cu-plated interconnects were demonstrated to be fully functional for powering a 5 SMD LEDs circuit. Furthermore, DLW enabled the interconnect manufacturing on an uneven substrate. This method is flexible, selective, low-cost, vacuum-free and of minimized environmental impact, and it provides a new route towards the manufacturing of biodegradable electronics.
AB - The electronic industry has room for improvement in adopting cleaner strategies, both in production processes (often energy-intensive and polluting) and in waste management. Many small components like security tags are routinely disposed of via general waste, which could be reduced adopting biodegradable polymers. In this work, a method for selective deposition of metallic micro-tracks on polycaprolactone (PCL) for circuitry integration is presented. The polymer is biodegradable, flexible, suitable for 3D printing, and can be obtained from sustainable sources. Photoreduction of Ag ions was used to generate seeds for subsequent selective electroless copper (Cu) plating in a process that avoids common but undesirable compounds such as cyanides and palladium. Two different photopatterning methods were successfully used to achieve selective Cu plating: flood exposure with a 460 nm light-emitting diode (LED) and direct laser writing (DLW) using a 405 nm laser, achieving 47 ± 11 μm wide tracks. The deposition of uniform Cu layers on PCL substrates is demonstrated, with thicknesses of up to 14 μm and electrical conductivities of up to 2.06 × 107 S m-1, which is near the conductivity of bulk Cu (5.89 × 107 S m-1). Cu-plated interconnects were demonstrated to be fully functional for powering a 5 SMD LEDs circuit. Furthermore, DLW enabled the interconnect manufacturing on an uneven substrate. This method is flexible, selective, low-cost, vacuum-free and of minimized environmental impact, and it provides a new route towards the manufacturing of biodegradable electronics.
KW - biodegradable
KW - electroless copper plating
KW - laser writing
KW - polycaprolactone (PCL)
KW - selective metallization
UR - http://www.scopus.com/inward/record.url?scp=85130562862&partnerID=8YFLogxK
U2 - 10.1088/2058-8585/ac6b6e
DO - 10.1088/2058-8585/ac6b6e
M3 - Article
AN - SCOPUS:85130562862
SN - 2058-8585
VL - 7
JO - Flexible and Printed Electronics
JF - Flexible and Printed Electronics
IS - 2
M1 - 025006
ER -