How do self-assembled monolayers change charge generation?

Self-assembled monolayers (SAMs) change charge generation in triboelectric materials by modifying the surface work function, surface energy, and chemical properties, leading to enhanced charge transfer during contact electrification. By carefully selecting the molecules that make up the SAM, it is possible to tune the surface work function of the triboelectric material, which directly influences its tendency to gain or lose electrons. A SAM can be designed to increase the electron affinity of a material, making it more likely to accept electrons and become negatively charged. Conversely, a SAM can be designed to decrease the electron affinity, making the material more likely to donate electrons and become positively charged. SAMs can also alter the surface energy of the material, affecting its adhesion and contact area with other materials. Furthermore, SAMs can introduce specific chemical functionalities that promote charge transfer. For example, a SAM with a high density of hydroxyl groups (-OH) can enhance the triboelectric performance of a material by facilitating the formation of hydrogen bonds and increasing the surface charge density.