A recent study published in Communications Materials explored the development of printable graphene inks using polypropylene carbonate (PPC) as a dispersant.
These inks remain stable in low-surface-tension solvents and can be processed at low temperatures, making them suitable for heat-sensitive substrates.
This advancement expands the potential of graphene-based inks for flexible electronics and printed electronic devices.
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Background
Graphene is a two-dimensional material with exceptional electrical conductivity, mechanical strength, and flexibility, making it ideal for flexible electronics.
Liquid-phase exfoliation (LPE) is a widely used method for producing high-quality graphene in large quantities, but formulating stable inks for printing remains a challenge. Many dispersants require high-temperature processing, limiting their use on heat-sensitive substrates.
Polypropylene carbonate (PPC), a biodegradable polymer derived from propylene oxide and carbon dioxide, offers a solution to this problem. Its low decomposition temperature allows graphene inks to be processed at mild temperatures, expanding their applicability.
This study highlights the potential of PPC-based inks in enabling fully printed electronic devices.
Developing Graphene Inks with PPC
Researchers first prepared graphene using LPE, where graphite was exfoliated in a solvent medium using sonication or shear forces. The resulting graphene flakes were collected, dried into a powder, and then re-dispersed into solvents optimized for electrical conductivity, viscosity, and printability.
PPC was incorporated into the ink formulation to improve dispersion stability and redispersibility. Fourier-transform infrared (FTIR) spectroscopy confirmed strong interactions between PPC and graphene through CH–π interactions, which enhanced graphene exfoliation and dispersion.
To evaluate the inks' printability, researchers tested them on various substrates, including silicon/silicon dioxide, glass, plastic, and paper. The primary solvent used was tetrahydrofuran (THF), along with a low-volatility co-solvent to maintain droplet stability during printing.
After printing, the graphene layers were annealed at 220 °C to remove PPC and establish a continuous, conductive network.
Key Findings: Improved Stability and Conductivity
Graphene inks formulated with PPC showed superior dispersion stability than those made with conventional dispersants. FTIR spectroscopy confirmed the enhanced redispersibility of graphene, contributing to better ink performance on multiple substrate types, including paper.
Printed graphene structures exhibited precise geometries and thickness control, which could be adjusted based on the number of printing passes. After annealing, the electrical conductivity of the printed graphene reached approximately 2.05 × 104 S/m, a significant improvement given that many previous formulations required post-processing above 300 °C to achieve similar results.
This demonstrates that PPC enables high conductivity with minimal thermal processing, making it compatible with flexible and heat-sensitive materials.
The study also demonstrated the successful fabrication of fully printed graphene micro-supercapacitors (MSCs) on parchment paper. These lightweight, renewable substrates supported interdigitated graphene electrodes that maintained strong adhesion after annealing, reinforcing the practical applications of PPC-based inks for flexible electronics.
What’s Next for Printable Graphene Inks?
The use of PPC in graphene inks marks a significant step forward for printed electronics. By allowing low-temperature processing on delicate substrates, these inks open the door for new high-performance electronic devices, including energy storage components like micro-supercapacitors.
Future research should focus on optimizing ink formulations, refining printing techniques, and scaling up production for commercial applications. As demand grows for sustainable, flexible, and high-performance electronics, PPC-based graphene inks could be key in advancing printed circuit technology, wearable sensors, and next-generation energy storage solutions.
Journal Reference
He H., et al. (2025). Printable graphene inks with polypropylene carbonate for low-surface-tension solvents and mild-temperature post-processing. Communications Materials. DOI: 10.1038/s43246-025-00753-y, https://www.nature.com/articles/s43246-025-00753-y