Electrowetting

1 A prelude on wetting
1.1 Homogeneous surfaces - Young-Laplace equation & Young-Dupré equation
1.2. Wetting in external fields - gravity & electric fields (leaky dielectric model)
1.3 Nano-scale wetting: effective interface potential
1.4 Wetting of heterogeneous surfaces - c.a. hysteresis & heterogeneity; Gibbs pinning criterion; metastability; Wenzel, Cassie-Baxter eq.,
1.5 Dynamic wetting

2 From electrocapillarity to electrowetting - a historic perspective
2.1 Lippmann's experiments; Lippmann equation in physical chemistry
2.2 Early applications (EC electrometer)
2.3 Early electrowetting (Frumkin)


3 Basic principles of modern electrowetting
3.1 Electrowetting on dielectric:
3.1.1 Derivation of EW equation
3.1.2 Effective surface tension picture
3.1.3 Origin of the minus sign
3.1.4 From Debye layer capacitance to dielectric layer: where is the energy (gain)?
3.1.5 AC vs. DC electrowetting
3.2 Microscopic picture
3.2.1 Local electric field & modified Laplace eq.
3.2.2 Consequences: diverging local fields
3.2.3 Reconciliation micro-macro
3.3 c.a. saturation: the big mystery of EW

4 Classical wetting phenomena controlled by electrowetting
4.1 Morphology transition on structured surfaces (wetting of fibers; EW of superhydrophobic surfaces)
4.2 Drop actuation by wettability gradients
4.3 Drop dynamics (oscillations, relaxation times, damped vs. overdamped)
4.4 Contact line dynamics (in air - in oil)

5 Numerical simulations of electrowetting (?)

6 Electrowetting materials
6.1 Insulators (dielectric breakdown; charge trapping; self-healing)
6.2 Liquids (small ions vs. large ions; colloidal stability; solubility (water in oil); surfactants)

7 Applications of EW
7.1 Lab-on-a-Chip devices
7.1.1 Classical device design & drop manipulation
7.1.2 Systems integration (bus architecture; programming)
7.1.3 Bio-challenges (surfactants; protein adsorption; cells)
7.1.4 Combined EW + detection (SPR, MALDI)
7.1.5 Electrowetting in two-phase flow microfluidics
7.2 Optoelectrowetting
7.2.1 Adaptive lenses
7.2.2 Autofocus systems
7.2.3 Beam stearing
7.2.4 Optical switches
7.2.5 Diffractive elements
7.2.6 Lens arrays
7.3 Electrowetting displays
7.3.1 Basics of display technology
7.3.2 The liquavista design
7.3.3 Cincinatti design

8 The future of EW
8.1 Novel applications
8.1.1 Reverse electrowetting: Energy harvesting systems
8.1.2 Reserve batteries & supercapacitor?
8.1.3 MALDI for EW
8.1.4 Reversible sponge
8.1.5 Mechanical actuators
8.2 Breaking the limits: nano EW; beyond c.a. hysteresis

Frieder Mugele is the head of the Physics of Complex Fluids group at the University of Twente in Enschede, The Netherlands. Having obtained his academic degrees in physics at the University of Konstanz, Germany, he spent several years at the University of California in Berkeley, USA, and the University of Ulm, Germany, before his present appointment in Twente. Professor Mugele's research focuses on various aspects of solid-liquid interfaces and the properties of liquids on the micro- and nanoscale. He has been active in electrowetting since the late 1990s contributing in particular to the theoretical understanding and to fundamental concepts of electrowetting-driven microfluidics.

Jason Heikenfeld is a Professor and Assistant Vice President for Commercialization at the Univ. of Cincinnati. He directs the Novel Devices Laboratory which has established highly-focused international leadership roles in an emergent technological paradigms including electrowetting, electronic paper, and most recently sweat biosensing technology. Prof. Heikenfeld's research approach centers on discovering and addressing the hidden challenges that can hinder the transition of innovative science into commercial application. Professor Heikenfeld is also a prolific inventor and serial entrepreneur, and during his teaching years was the highest-rated STEM educator at the University of Cincinnati.

F. Mugele, University of Twente, Enschede, The Netherlands; J. Heikenfeld, University of Cincinnati, USA