About

Dr. Chuan-Hua Chen is an Associate Professor and Hunt Faculty Scholar of Mechanical Engineering and Materials Science at Duke University, where he leads the Microscale Physicochemical Hydrodynamics Laboratory (µPHYL). He earned his B.S. degree in Applied Mechanics from Peking University in 1998 and his Ph.D. in Mechanical Engineering from Stanford University in 2004. Before joining Duke in 2007, Dr. Chen worked as a postdoctoral associate at Princeton University and as a research scientist at Rockwell Scientific Company. He has been recognized with prestigious awards including the NSF CAREER Award and the DARPA Young Faculty Award for his innovative research that integrates physicochemical hydrodynamics with interfacial engineering. His work has gained significant attention, being featured on the covers of Physical Review Letters and Applied Physics Letters, and covered by both professional and popular media such as Science and The New York Times.

Research topics

• Materials science
• Mechanics
• Nanotechnology
• Physics
• Composite material

Selected publications

• 10.1063/1.5080241.2

  Default Digital Object Group · 2019-03-20

  datasetSenior author

  A superhydrophobic surface is non-sticking to aqueous droplets due to minimized solid-liquid contact, but the small contact area also poses challenges to droplet maneuvering. This letter reports a technique using electric field gradients to actuate aqueous droplets on superhydrophobic surfaces. A pin-ring electrode pair underneath the insulating superhydrophobic surface is used to generate electric field gradient above the surface, with the field focused around the pin. The non-uniform field operates on the electrostatically induced charges on the droplet, producing an actuation force attracting the droplet toward the pin. The actuation force is proportional to the square of the imposed field as shown in both experiments and simulations. This non-contact actuation technique is effective in electrostatically trapping and translating superhydrophobic droplets, despite the small solid-liquid contact. The pin-ring configuration can be readily extended to a pin array between two parallel lines, which essentially form a stretched ring closing at infinity. The pin array is used to demonstrate individual actuation of two droplets leading to their eventual coalescence.

  PublisherDOI

• 10.1063/1.5080241.3

  Default Digital Object Group · 2019-03-20

  datasetSenior author

  A superhydrophobic surface is non-sticking to aqueous droplets due to minimized solid-liquid contact, but the small contact area also poses challenges to droplet maneuvering. This letter reports a technique using electric field gradients to actuate aqueous droplets on superhydrophobic surfaces. A pin-ring electrode pair underneath the insulating superhydrophobic surface is used to generate electric field gradient above the surface, with the field focused around the pin. The non-uniform field operates on the electrostatically induced charges on the droplet, producing an actuation force attracting the droplet toward the pin. The actuation force is proportional to the square of the imposed field as shown in both experiments and simulations. This non-contact actuation technique is effective in electrostatically trapping and translating superhydrophobic droplets, despite the small solid-liquid contact. The pin-ring configuration can be readily extended to a pin array between two parallel lines, which essentially form a stretched ring closing at infinity. The pin array is used to demonstrate individual actuation of two droplets leading to their eventual coalescence.

  PublisherDOI

• An improved TLD algorithm with selective detection

  Journal of Physics Conference Series · 2019-02-01

  articleOpen accessSenior author

  This paper proposes an improved TLD algorithm with selective detection. In the tracking module, KCF is used as the short-term tracker, and the idea of backward tracking is introduced to judge the accuracy of the result, when the result is inaccurate, the proposed algorithm starts up the detection module; in the detection module, H component of the color image is used as the input, and the mean filter serves as the first layer of the cascaded classifier, the color histogram similarity measure method is used to judge the accuracy of the detection results; finally a fusion strategy is formulated according to the output results of the tracking module and the detection module. The experiments carried on the OTB-2013 data platform show that the tracking accuracy and success rate of the proposed algorithm are respectively 0.801 and 0.591, which are 20.4% and 16.5% higher than the TLD algorithm, besides the proposed algorithm have good adaptability in scenarios such as illumination change, occlusion, and scale change, which shows superior tracking robustness.

  PublisherDOI

• Droplet actuation on superhydrophobic substrates via electric field gradients

  Applied Physics Letters · 2019-03-18 · 21 citations

  articleSenior author

  A superhydrophobic surface is non-sticking to aqueous droplets due to minimized solid-liquid contact, but the small contact area also poses challenges to droplet maneuvering. This letter reports a technique using electric field gradients to actuate aqueous droplets on superhydrophobic surfaces. A pin-ring electrode pair underneath the insulating superhydrophobic surface is used to generate electric field gradient above the surface, with the field focused around the pin. The non-uniform field operates on the electrostatically induced charges on the droplet, producing an actuation force attracting the droplet toward the pin. The actuation force is proportional to the square of the imposed field as shown in both experiments and simulations. This non-contact actuation technique is effective in electrostatically trapping and translating superhydrophobic droplets, despite the small solid-liquid contact. The pin-ring configuration can be readily extended to a pin array between two parallel lines, which essentially form a stretched ring closing at infinity. The pin array is used to demonstrate individual actuation of two droplets leading to their eventual coalescence.

  PublisherDOI

• Evaporation-Induced Breakup of a Droplet in a Shallow Well

  APS Division of Fluid Dynamics Meeting Abstracts · 2019-11-01

  articleSenior author
  Publisher

• 10.1063/1.5080241.1

  Default Digital Object Group · 2019-03-20

  datasetSenior author

  A superhydrophobic surface is non-sticking to aqueous droplets due to minimized solid-liquid contact, but the small contact area also poses challenges to droplet maneuvering. This letter reports a technique using electric field gradients to actuate aqueous droplets on superhydrophobic surfaces. A pin-ring electrode pair underneath the insulating superhydrophobic surface is used to generate electric field gradient above the surface, with the field focused around the pin. The non-uniform field operates on the electrostatically induced charges on the droplet, producing an actuation force attracting the droplet toward the pin. The actuation force is proportional to the square of the imposed field as shown in both experiments and simulations. This non-contact actuation technique is effective in electrostatically trapping and translating superhydrophobic droplets, despite the small solid-liquid contact. The pin-ring configuration can be readily extended to a pin array between two parallel lines, which essentially form a stretched ring closing at infinity. The pin array is used to demonstrate individual actuation of two droplets leading to their eventual coalescence.

  PublisherDOI

• Thin-Film Breakup Dynamics of a Binary Mixture Drop during Evaporation

  APS Division of Fluid Dynamics Meeting Abstracts · 2019-11-01

  articleSenior author
  Publisher

• Asymmetric drop coalescence launches fungal ballistospores with directionality

  Journal of The Royal Society Interface · 2017-07-01 · 45 citations

  articleOpen accessSenior authorCorresponding

  Thousands of fungal species use surface energy to power the launch of their ballistospores. The surface energy is released when a spherical Buller's drop at the spore's hilar appendix merges with a flattened drop on the adaxial side of the spore. The launching mechanism is primarily understood in terms of energetic models, and crucial features such as launching directionality are unexplained. Integrating experiments and simulations, we advance a mechanistic model based on the capillary-inertial coalescence between the Buller's drop and the adaxial drop, a pair that is asymmetric in size, shape and relative position. The asymmetric coalescence is surprisingly effective and robust, producing a launching momentum governed by the Buller's drop and a launching direction along the adaxial plane of the spore. These key functions of momentum generation and directional control are elucidated by numerical simulations, demonstrated on spore-mimicking particles, and corroborated by published ballistospore kinematics. Our work places the morphological and kinematic diversity of ballistospores into a general mechanical framework, and points to a generic catapulting mechanism of colloidal particles with implications for both biology and engineering.

  PublisherOA PDFDOI

• Utilization of self-powered electrochemical systems: Metallic nanoparticle synthesis and lactate detection

  Nano Energy · 2017-10-31 · 118 citations

  article1st author
  PublisherDOI

• Hotspot cooling with jumping-drop vapor chambers

  Applied Physics Letters · 2017-04-03 · 141 citations

  articleSenior author

  Hotspot cooling is critical to the performance and reliability of electronic devices, but existing techniques are not very effective in managing mobile hotspots. We report a hotspot cooling technique based on a jumping-drop vapor chamber consisting of parallel plates of a superhydrophilic evaporator and a superhydrophobic condenser, where the working fluid is returned via the spontaneous out-of-plane jumping of condensate drops. While retaining the passive nature of traditional vapor-chamber heat spreaders (flat-plate heat pipes), the jumping-drop technique offers a mechanism to address mobile hotspots with a pathway toward effective thermal transport in the out-of-plane direction.

  PublisherDOI

Recent grants

• SGER: Biomimetic Electrospray Vapor Chamber

  NSF · $40k · 2008–2009

• CAREER: Electrohydrodynamic Coulter Counting

  NSF · $418k · 2009–2014

• Adaptive Hotspot Cooling with Self-Propelled Jumping Condensate

  NSF · $250k · 2012–2015

Frequent coauthors

• Jonathan B. Boreyko

  Virginia Tech

  29 shared

• Fangjie Liu

  Oak Ridge National Laboratory

  16 shared

• James J. Feng

  14 shared

• Juan G. Santiago

  13 shared

• Xiaopeng Qu

  Northwest A&F University

  11 shared

• Yuejun Zhao

  11 shared

• H. Alex Guo

  Jinling Institute of Technology

  8 shared

• Scott T. Retterer

  Oak Ridge National Laboratory

  7 shared

Labs

• Microscale Physicochemical Hydrodynamics LaboratoryPI

  Not provided

Education

• Ph.D., Mechanical Engineering

  Stanford University

  2004

Awards & honors

• Faculty Early Career Development (CAREER) Program. National…