Double mass transfer during polymer-polymer contacts

Salaneck, W. R.; Paton, A.; Clark, D. T.

doi:10.1063/1.322306

Cited by 77 publications

(51 citation statements)

References 7 publications

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“…19,[58][59][60][61][62] It has been explained in terms of, for instance, charge-carrier diffusion along thermal gradients, 29 a suggestion that did not hold true in experiments. 59 For two polymers rubbed against each other, transfer of material in both directions has been observed, 63 and it has been suggested that charge might be transferred along with it. [9][10][11]25 The net charge on PTFE, generated by sliding metal contacts, has been found to be proportional to the square root of the load force, which in turn has been shown to be proportional to the contact area.…”

Section: B Related Literature Resultsmentioning

confidence: 99%

Squeezing out hydrated protons: low-frictional-energy triboelectric insulator charging on a microscopic scale

Knorr¹

2011

AIP Advances

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Though triboelectric charging of insulators is common, neither its mechanism nor the nature of the charge is well known. Most research has focused on the integral amount of charge transferred between two materials upon contact, establishing, e.g., a triboelectric series. Here, the charge distribution of tracks on insulating polymer films rubbed by polymer-covered pointed swabs is investigated in high resolution by Kelvin probe force microscopy. Pronounced bipolar charging was observed for all nine rubbing combinations of three different polymers, with absolute surface potentials of up to several volts distributed in streaks along the rubbing direction and varying in polarity on μm-length scales perpendicular to the rubbing direction. Charge densities increased considerably for rubbing in higher relative humidity, for higher rubbing loads, and for more hydrophilic polymers. The ends of rubbed tracks had positively charged rims. Surface potential decay with time was strongly accelerated in increased humidity, particularly for polymers with high water permeability. Based on these observations, a mechanism is proposed of triboelectrification by extrusions of prevalently hydrated protons, stemming from adsorbed and dissociated water, along pressure gradients on the surface by the mechanical action of the swab. The validity of this mechanism is supported by explanations given recently in the literature for positive streaming currents of water at polymer surfaces and by reports of negative charging of insulators tapped by accelerated water droplets and of potential built up between the front and the back of a rubbing piece, observations already made in the 19th century. For more brittle polymers, strongly negatively charged microscopic abrasive particles were frequently observed on the rubbed tracks. The negative charge of those particles is presumably due in part to triboemission of electrons by polymer chain scission, forming radicals and negatively charged ions

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Section: B Related Literature Resultsmentioning

confidence: 99%

Squeezing out hydrated protons: low-frictional-energy triboelectric insulator charging on a microscopic scale

Knorr¹

2011

AIP Advances

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“…For example, when some polymers are rubbed with friction, an exchange of deeper layer materials occurs [52]. (This helps explain why even the same polymers can be charged by tribo-contacts; it is because even identical polymers will have different material compositions at each depth, which account for the same material charge transfer [29].)…”

Section: (Nano-) Materialsmentioning

confidence: 99%

Fundamental theories and basic principles of triboelectric effect: A review

2018

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Long-term observation of the triboelectric effect has not only proved the feasibility of many novel and useful tribo-devices (e.g., triboelectric nanogenerators), but also constantly motivated the exploration of its mysterious nature. In the pursuit of a comprehensive understanding of how the triboelectric process works, a more accurate description of the triboelectric effect and its related parameters and factors is urgently required. This review critically goes through the fundamental theories and basic principles governing the triboelectric process. By investigating the difference between each charging media, the electron, ion, and material transfer is discussed and the theoretical deduction in the past decades is provided. With the information from the triboelectric series, interesting phenomena including cyclic triboelectric sequence and asymmetric triboelectrification are precisely analyzed. Then, the interaction between the tribo-system and its operational environment is analyzed, and a fundamental description of its effects on the triboelectric process and results is summarized. In brief, this review is expected to provide a strong understanding of the triboelectric effect in a more rigorous mathematical and physical sense.

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“…In general, tribocharging is the process whereby a charge exists on a material after departing from the contact with a dissimilar material and the two materials can be any combination of conductor, semiconductor, or insulator (dielectric). Although it is thought that contact charging is the result of electron transferring from one body to the other (Rose-Innes, 1980), there is evidence in some cases that the charge transfer in contact charging can occur by ion transfer (Harper, 1967;Gaudin, 1971) and material transfer (Salanek et al, 1976). It is a common observation that the tribocharging process involves at least two physical mechanisms, which are equally vital in determining the determined by the work function parameters until the Fermi levels at the surface are equal.…”

Section: Theoretical Overviewmentioning

confidence: 99%

“…Material transfer in some cases (such as, when polymers and metals are brought into contact) is of possible notability to contact electrification, if the number of transferred atoms per unit area exceeds the charge density (in units of e per unit area) observed in the contact electrification (Lowell and Rose-Innes, 1980 (Salanek et al, 1976). With the use of ESCA for surface analysis, they showed that some of the metal transferred to the polymer and, likewise, some of the polymer to metal when they were in contact with each other.…”

Section: A) Materials Transfermentioning

confidence: 99%