The Role of Adhesion in Triboelectrification Trends: Charge Polarity and Magnitude

Triboelectricity – the generation of charge through the contact-separation – underpins technologies including energy harvesting and sensing. While the charge magnitude is known to depend on surface chemistry, morphology, and mechanical properties, the role of adhesion – particularly on charge polarity – remains unclear. Here, we investigate adhesion effects using polydimethylsiloxane (PDMS) films with different base polymer to curing agent ratios (5:1, 10:1, and 15:1), yielding distinct viscoelastic and adhesive properties without altering chemical structure. Nanoindentation and pull-off tests revealed that reduced cross-linking enhances viscoelastic deformation and work of adhesion. Triboelectric measurements demonstrated that more adhesive PDMS surfaces generate more negative charge densities. When PDMS films of differing adhesion were contacted, the more adhesive surface charged negatively, while the less adhesive one positively, enabling polarity control without chemical modifications. Increased contact duration further enhances both adhesion and charge density. These findings reveal that adhesion engineering, offers a simple strategy for optimizing triboelectric charging trends.