Effect of excitation frequency and pneumatic pressure on the voltage response of a chemically unmodified chicken feather-based contact-separation triboelectric nanogenerator

Chemically unmodified waste chicken feathers (CF) offer a potential route for valorising poultry waste as a triboelectric material while avoiding deliberate chemical functionalisation. This study investigates the voltage response of a CF–PTFE contact–separation triboelectric nanogenerator (CS-TENG) under controlled variations in excitation frequency, pneumatic pressure, and CF layer configuration. A full- factorial combination of three excitation frequencies (0.5, 2.7, and 5.0 Hz), three pneumatic pressures (0.2, 0.4, and 0.6 MPa), and three CF configurations (1CF, 3CF, and 5CF) was evaluated, with each condition tested in three separate experimental runs. Within the investigated ranges, the mean peak-to-peak voltage (Vpp) increased consistently with excitation frequency and pneumatic pressure across all CF configurations. The 3CF configuration produced the highest mean Vpp among the tested configurations, reaching 60.33 ± 0.58 V at 5.0 Hz and 0.6 MPa. These findings establish the experimentally observed voltage response of chemically unmodified waste CF in a CS-TENG and demonstrate systematic variations in response with excitation frequency, pneumatic pressure, and CF layer configuration within the investigated ranges. The results are limited to voltage measurements within these parameter ranges; therefore, further current, charge, load-dependent power, and extended-range measurements are required to establish broader energy-harvesting performance.