Correlating Material Transfer and Charge Transfer in Contact Electrification

Abstract

Static charge on surfaces of materials is generated when two solid surfaces come into contact and are then separated. It is important to understand the phenomenon because the influence of static charge on surfaces is widely felt in our daily lives and can have a wide range of applications or undesirable effects in industry. Although the phenomenon has been observed since antiquity, the fundamental mechanism that underlies the generation of charge on insulating surfaces is still not known. After many decades of research, different mechanisms have been proposed, including electron and ion transfer. One other possibility has been discussed to a lesser extent: material transfer (i.e., the transfer of quantities of charged materials). This study seeks to investigate the significance of material transfer by correlating the amount of charge transferred and the amount of material transferred from one surface to another after contact. The investigation involved varying the degree of softness of a polymer (polydimethylsiloxane; PDMS), contact-charging it against another reference material, and analyzing the surfaces of the materials after contact. Results showed that when more material transferred, more charge was generated. An explanation for these results is that the surface of PDMS experienced heterolytic cleavage of bonds, which resulted in the generation of charge. When more cleavage of bonds occurred, more charge was generated, and more materials were transferred. Hence, material transfer seems to have an important contribution for the generation of charge by contact.

Interface inter-atomic electron-transition induced photon emission in contact-electrification

“…The research on the mechanism of CE recently enormously evolved with modern technologies (13,14). With some unexplainable even contradictory observations (15)(16)(17)(18)(19), it seems that no one mechanism can explain such a complex phenomenon (20). Is there really no way that we could access the fundamental or dominant mechanism to generalize the CE concept for different types of materials?…”

Adhesion and Mechanical Properties of PDMS-Based Materials Probed with AFM: A Review

“…Adhesion of PDMS is also of great importance in the field of microfluidics where proper and tight contact between PDMS and glass substrate should be assured to avoid any leakage [31,32]. Since recent, PDMS has been widely used in triboelectric nanogenerators as contacting layers for mechanical energy harvesting [33][34][35] where adhesion may play a significant role in achieving higher surface charge [36,37], which is the key parameter for high performance. Adhesion plays important role in PDMS application for exfoliation, dry transfer and stamp printing of monolayers of 2D materials like graphene, transitional metal dichalcogenides (MoS 2 , WS 2 , etc), h-BN and other layered van-der-Waals materials [38][39][40][41].…”

Quantifying electron-transfer in liquid-solid contact electrification and the formation of electric double-layer

“…ontact electrification (CE) (or triboelectrification in general terms) is a universal but complicated phenomenon, which has been known for more than 2600 years. The solid-solid CE has been studied using various methods and different mechanisms were proposed (Electron transfer 1,2 , ion transfer 3 and material transfer [4][5][6] were used to explain different types of CE phenomena for various materials). In parallel, CE between liquid-solid is rather ubiquitous in our daily life, such as flowing water out of a pipe is charged, which is now the basis of many technologies and physical chemical phenomena, such as the liquid-solid triboelectric nanogenerators (TENGs) [7][8][9][10] , hydrophobic and hydrophilic surfaces, and the formation of electric double-layer (EDL) [11][12][13][14] .…”