Photoluminescent CDs@PEEK coating for wear-resistant and weather-resistant thermometer

To address the critical impact of temperature fluctuations on precision, stability, and friction coefficients (COF) in fluid machinery (e.g., pumps, compressors, motors), a carbon dots-embedded photoluminescent composite coating (CDs@PEEK) is developed for simultaneous non-contact temperature sensing and enhanced tribological performance on equipment surfaces. The CDs@PEEK coating exhibits temperature-responsive fluorescence, characterized by a linear intensity decrease from 50 to 120 °C with a sensitivity of 0.769 % °C −1 and excellent reproducibility of 98.01 % over five cycles. Additionally, it demonstrates superior tribological performance, achieving a lower COF (0.169 ± 0.004) compared to PEEK (0.178 ± 0.008) and stainless steel (0.335 ± 0.005), along with a reduced wear rate of 0.00548 ± 0.00010 mm 2 –4.0 % lower than PEEK and 64.6 % lower than stainless steel—indicating significantly enhanced wear resistance. The coating keeps stable fluorescence and temperature sensing after repeated heating, rubbing, and boiling. CDs@PEEK serves as a multifunctional coating for wear resistance and visual temperature monitoring, promising for smart fluid machinery.