The WP1 has the objective of defining the product specifications and functionality related to the prototype test cases, included the flexible printed electronic system parts, materials, processes of integration. This was duly down and reported in D1.1 together with the preliminary design of each use case.
In this WP2 the following types of inks have been developed:
- Conducitve ink:. Ink composition of graphite (18%) PCN (8%), PLA (6%), and cyrene (68%) yielded sheet resistance of 16 Ω/sq for a 30 µm thick printed layer.
- Dielectric ink: ink composition consists on Nanocellulose (CNC-Slurry-DS) (3%), Water (87%), Ethanol (5%) and Ethylene glycol (5%). Deposition with inkjet printing was performed and dielectric characterization has been performed, achieving the dielectric constant found on literature for cellulose (6.1 for 1 kHz).
- Piezoelectric PLA inks:-PLA based ink: several types of ink have been developed using different strategies: (i) emulsion based inks (low melting amorphous PLA), (ii) dispersions based inks (high melting (semi)-crystalline PLA) and (iii) solvent based inks (stereocomplex PLA).
WP3 deals with the development of vibrational piezoelectric energy harvesters (VPEHs) using non-critical, non-toxic and sustainable materials. The selected route involves (i) manufacturing of PLA-based piezoelectric films by extrusion – orientation, (ii) printing of foldable electrodes onto PLA-based insulation layers and (iii) bonding procedures to resonant PLA-based cantilevers.
WP4 actions have been focusing on the development of supercapacitors and the design of power conditioning circuits. The work has focused on: substrate development, current collectors, electrode material development, testing of different electrolytes, and design of power conditioning circuits:
In the WP5, the ability of a sustainable energy harvesting system to power low-energy sensors has been analyzed. Initial attempts using PLA-based harvesters proved insufficient, particularly at the low vibration frequencies typical in automotive environments.. The system successfully powered simple sensors such as temperature loggers, with future testing focused on evaluating NFC-based solutions, which could simplify power and data handling. However, integration remains complex due to differences in voltage requirements between sensors and communication circuits.
CBT started with the textile demonstrator being a fully PLA based composite seat shell with integrated PLA based cantilever with piezoelectric harvestor in PLA or PVDF (as mitigation strategy for when PLA does not provide sufficient current for the rectifier).
ORB worked in the desing of the energy harvesting system for integration into plastic automotive parts, specifically a camera bracke. Several innovative mechanical designs were proposed to maximize energy output within the limited space available.
GEM focused on developing a self-powered, embedded system capable of detecting structural damage in composite materials. A sensor unit was integrated into a test structure to monitor changes in its behavior under mechanical stress. The system successfully identified subtle changes that could indicate the early stages of damage, even before they became visible.
In the WP9 , the SSAIL (Selective Surface Activation Induced by Laser) process has been developed.The task focused on fine-tuning both the laser treatment and chemical activation/plating protocols for a selection of biopolymers, with the objective of achieving high selectivity, mechanical robustness, and electrical conductivity of plated circuits. A range of polymers, including TERRANYL®, Fibernyl®, Bio-polyethylene®, Mellanyl®, Bio panel®, PLA, PET, and PI, were tested. Laser parameters—wavelength, pulse duration, repetition rate, and irradiation dose were systematically varied to assess their influence on surface activation and subsequent electroless copper deposition.
REgarding rhe Bio ink based piezo resistive sensors, the primary focus has been on developing and optimizing laser-induced graphene (LIG) as the sensing electrode for a piezoresistive sensor. Alongside this, a commercial sustainable nanopaint-based conductive ink was procured to evaluate its environmental performance and assess its potential as an alternative material.
The activities of WP6 follow the strategy outlined in project’s Communication, Dissemination plan, which was originally drafted at M6 and then reviewed twice at M16 and at M32.
In, WP7 tCircular Economy evaluation matrix first and second version with Initial Technical research, URS, FRS and tentative PDS tools has been done.
