Electrowetting: A Consideration in Electroadhesion

With the commercialization of haptic devices, understanding behavior under various environmental conditions is crucial for product optimization and cost reduction. Specifically, for surface haptic devices, the dependence of the friction force and the electroadhesion effect on the environmental relative humidity and the finger hydration level can directly impact their design and performance. This article presents the influence of relative humidity on the finger-surface friction force and the electroadhesion performance. Mechanisms including changes to Young's modulus of skin, contact angle change and capillary force were analyzed separately with experimental and numerical methods. Through comparison of the calculated capillary force in this paper and the electroadhesion force calculated in published papers, it was found that electrowetting at high voltage could contribute up to 60% of the total friction force increase in electroadhesion. Therefore, in future design of surface haptic devices, the effect of electrowetting should be considered carefully.

[1]  S. Derler,et al.  Tribology of Skin: Review and Analysis of Experimental Results for the Friction Coefficient of Human Skin , 2011, Tribology Letters.

[2]  J. Edward Colgate,et al.  UltraShiver: Lateral force feedback on a bare fingertip via ultrasonic oscillation and electroadhesion , 2018, 2018 IEEE Haptics Symposium (HAPTICS).

[3]  Brian J. Briscoe,et al.  Friction and lubrication of human skin , 2007 .

[4]  J. Edward Colgate,et al.  The application of tactile, audible, and ultrasonic forces to human fingertips using broadband electroadhesion , 2017, 2017 IEEE World Haptics Conference (WHC).

[5]  Yonghui Yuan,et al.  Measuring microelastic properties of stratum corneum. , 2006, Colloids and surfaces. B, Biointerfaces.

[6]  Yon Visell,et al.  Complexity, rate, and scale in sliding friction dynamics between a finger and textured surface , 2018, Scientific Reports.

[7]  Ling-Sheng Jang,et al.  Simulation and experimentation of a microfluidic device based on electrowetting on dielectric , 2007, Biomedical microdevices.

[8]  J. Mo,et al.  Overview of finger friction and tactile perception , 2018, Biosurface and Biotribology.

[9]  B. Persson,et al.  Capillary adhesion between elastic solids with randomly rough surfaces , 2008, 0805.0684.

[10]  Michael J. Adams,et al.  Friction of the Human Finger Pad: Influence of Moisture, Occlusion and Velocity , 2011 .

[11]  Matt Carré,et al.  The contributions of skin structural properties to the friction of human finger-pads , 2015 .

[12]  S. E. Tomlinson,et al.  Understanding the Friction Mechanisms Between the Human Finger and Flat Contacting Surfaces in Moist Conditions , 2011 .

[13]  B. Persson.  Contact mechanics for randomly rough surfaces , 2006, cond-mat/0603807.

[14]  B. Berge,et al.  Electrowetting : a recent outbreak , 2001 .

[15]  Koichi Iinoya,et al.  The capillary binding force of a liquid bridge , 1974 .

[16]  Cagatay Basdogan,et al.  Electroadhesion with application to touchscreens. , 2019, Soft matter.

[17]  Alain Delchambre,et al.  Comparison between two capillary forces models. , 2008, Langmuir : the ACS journal of surfaces and colloids.

[18]  J. Baret,et al.  Electrowetting: from basics to applications , 2005 .

[19]  J. Edward Colgate,et al.  eShiver: Lateral Force Feedback on Fingertips through Oscillatory Motion of an Electroadhesive Surface , 2017, IEEE Transactions on Haptics.

[20]  Stanislav N. Gorb,et al.  Contact Mechanics and Friction on Dry and Wet Human Skin , 2013, Tribology Letters.

[21]  B. Berge,et al.  Electrowetting of water and aqueous solutions on poly(ethylene terephthalate) insulating films , 1996 .

[22]  Bharat Bhushan,et al.  Nanotribological and nanomechanical properties of skin with and without cream treatment using atomic force microscopy and nanoindentation. , 2012, Journal of colloid and interface science.

[23]  J. Edward Colgate,et al.  On the electrical characterization of electroadhesive displays and the prominent interfacial gap impedance associated with sliding fingertips , 2018, 2018 IEEE Haptics Symposium (HAPTICS).

[24]  Adam S. Foster,et al.  Towards an accurate description of the capillary force in nanoparticle-surface interactions , 2005 .

[25]  B. Saramago,et al.  Electrowetting of Ionic Liquids: Contact Angle Saturation and Irreversibility , 2009 .

[26]  B N J Persson,et al.  The dependency of adhesion and friction on electrostatic attraction. , 2018, The Journal of chemical physics.

[27]  K. Kobe.  The friction and lubrication of solids , 1951 .