This chapter highlights a variety of techniques that are commonly used to measure contact angles, including the conventional telescope-goniometer method, the Wilhelmy balance method, and the more recently developed drop-shape analysis methods. The various applications and limitations of these techniques are described. Notably, studies of ultrasmall droplets on solid surfaces allow wetting theories to be tested down to the nanometer scale, bringing new insight to contact angle phenomena and wetting behavior.

https://www.springer.com/cda/content/document/cda_downloaddocument/9783642342424-c1.pdf?SGWID=0-0-45-1368817-p174704744

Contact Angle and Wetting Properties

Part I: Background and Fundamentals Introduction, Mohamed Gad-el-Hak, University of Notre Dame Scaling of Micromechanical Devices, William Trimmer, Standard MEMS, Inc., and Robert H. Stroud, Aerospace Corporation Mechanical Properties of MEMS Materials, William N. Sharpe, Jr., Johns Hopkins University Flow Physics, Mohamed Gad-el-Hak, University of Notre Dame Integrated Simulation for MEMS: Coupling Flow-Structure-Thermal-Electrical Domains, Robert M. Kirby and George Em Karniadakis, Brown University, and Oleg Mikulchenko and Kartikeya Mayaram, Oregon State University Liquid Flows in Microchannels, Kendra V. Sharp and Ronald J. Adrian, University of Illinois at Urbana-Champaign, Juan G. Santiago and Joshua I. Molho, Stanford University Burnett Simulations of Flows in Microdevices, Ramesh K. Agarwal and Keon-Young Yun, Wichita State University Molecular-Based Microfluidic Simulation Models, Ali Beskok, Texas A&M University Lubrication in MEMS, Kenneth S. Breuer, Brown University Physics of Thin Liquid Films, Alexander Oron, Technion, Israel Bubble/Drop Transport in Microchannels, Hsueh-Chia Chang, University of Notre Dame Fundamentals of Control Theory, Bill Goodwine, University of Notre Dame Model-Based Flow Control for Distributed Architectures, Thomas R. Bewley, University of California, San Diego Soft Computing in Control, Mihir Sen and Bill Goodwine, University of Notre Dame Part II: Design and Fabrication Materials for Microelectromechanical Systems Christian A. Zorman and Mehran Mehregany, Case Western Reserve University MEMS Fabrication, Marc J. Madou, Nanogen, Inc. LIGA and Other Replication Techniques, Marc J. Madou, Nanogen, Inc. X-Ray-Based Fabrication, Todd Christenson, Sandia National Laboratories Electrochemical Fabrication (EFAB), Adam L. Cohen, MEMGen Corporation Fabrication and Characterization of Single-Crystal Silicon Carbide MEMS, Robert S. Okojie, NASA Glenn Research Center Deep Reactive Ion Etching for Bulk Micromachining of Silicon Carbide, Glenn M. Beheim, NASA Glenn Research Center Microfabricated Chemical Sensors for Aerospace Applications, Gary W. Hunter, NASA Glenn Research Center, Chung-Chiun Liu, Case Western Reserve University, and Darby B. Makel, Makel Engineering, Inc. Packaging of Harsh-Environment MEMS Devices, Liang-Yu Chen and Jih-Fen Lei, NASA Glenn Research Center Part III: Applications of MEMS Inertial Sensors, Paul L. Bergstrom, Michigan Technological University, and Gary G. Li, OMM, Inc. Micromachined Pressure Sensors, Jae-Sung Park, Chester Wilson, and Yogesh B. Gianchandani, University of Wisconsin-Madison Sensors and Actuators for Turbulent Flows. Lennart Loefdahl, Chalmers University of Technology, and Mohamed Gad-el-Hak, University of Notre Dame Surface-Micromachined Mechanisms, Andrew D. Oliver and David W. Plummer, Sandia National Laboratories Microrobotics Thorbjoern Ebefors and Goeran Stemme, Royal Institute of Technology, Sweden Microscale Vacuum Pumps, E. Phillip Muntz, University of Southern California, and Stephen E. Vargo, SiWave, Inc. Microdroplet Generators. Fan-Gang Tseng, National Tsing Hua University, Taiwan Micro Heat Pipes and Micro Heat Spreaders, G. P. "Bud" Peterson, Rensselaer Polytechnic Institute Microchannel Heat Sinks, Yitshak Zohar, Hong Kong University of Science and Technology Flow Control, Mohamed Gad-el-Hak, University of Notre Dame) Part IV: The Future Reactive Control for Skin-Friction Reduction, Haecheon Choi, Seoul National University Towards MEMS Autonomous Control of Free-Shear Flows, Ahmed Naguib, Michigan State University Fabrication Technologies for Nanoelectromechanical Systems, Gary H. Bernstein, Holly V. Goodson, and Gregory L. Snider, University of Notre Dame Index

The MEMS Handbook

Creating functional electrical circuits using individual or ensemble molecules, often termed as “molecular-scale electronics”, not only meets the increasing technical demands of the miniaturization of traditional Si-based electronic devices, but also provides an ideal window of exploring the intrinsic properties of materials at the molecular level. This Review covers the major advances with the most general applicability and emphasizes new insights into the development of efficient platform methodologies for building reliable molecular electronic devices with desired functionalities through the combination of programmed bottom-up self-assembly and sophisticated top-down device fabrication. First, we summarize a number of different approaches of forming molecular-scale junctions and discuss various experimental techniques for examining these nanoscale circuits in details. We then give a full introduction of characterization techniques and theoretical simulations for molecular electronics. Third, we highlig...

Molecular-Scale Electronics: From Concept to Function

A rapidly emerging field in lab-on-a-chip (LOC) research is the development of devices to improve the health of people in developing countries. In this review, we identify diseases that are most in need of new health technologies, discuss special design criteria for LOC devices to be deployed in a variety of resource-poor settings, and review past research into LOC devices for global health. We focus mainly on diagnostics, the nearest-term application in this field.

Lab-on-a-chip devices for global health: Past studies and future opportunities

http://wolfson.huji.ac.il/purification/Course92632_2014/Aggregation/MAHLER2009.pdf

Protein aggregation: Pathways, induction factors and analysis

The self-assembling of three-dimensional (3-D) MEMS from polysilicon surface micromachined part is very attractive. To avoid risky external manipulation, the practical use of integrated actuator to perform the assembling task is required. To that goal, this paper presents detailed characteristics of the electrostatic surface micromachined scratch drive actuator (SDA). First, from numerous SDA tests, it is shown that this actuator is able to produce a threshold force of 30 /spl mu/N, with a yield above 60%. With polysilicon devices consisting of SDA mechanically linked to buckling beam, a horizontal force of 63 mN has been demonstrated with /spl plusmn/112 V pulse, and up to 100 /spl mu/N can be obtained with higher voltage. With buckling beams, displacements up to 150 /spl mu/m have been obtained in the vertical direction. The generation of vertical force of 10 /spl mu/N was confirmed with a 100 /spl mu/m displacement producing 1 nJ work in the vertical direction. Finally, SDA overcomes the usual sticking of surface machined polysilicon by producing enough vertical force to completely release wide polysilicon plate (500 /spl mu/m/spl times/50 /spl mu/m) without external manipulation. The above characteristic, both in terms of structure releasing and vertical/horizontal forces and displacements provides the SDA with the capability of self-assembling complex 3-D polysilicon part, opening new integration capabilities and new application field of MEMS.

Scratch drive actuator with mechanical links for self-assembly of three-dimensional MEMS

This paper presents a polysilicon slider and a rotor capable of stepwise motion. These devices were fabricated on a silicon wafer with surface micromachine technology. The proportional relation between the velocity of motion and the frequency of the applied pulse was experimentally confirmed. The peak value of the applied pulse determines the step length. The step values observed were in the range of 10-30 nm for a bushing height of 1.0 mu m and of 40-80 nm for a bushing height of 2.0 mu m depending on the peak voltage of the applied pulse. >

Controlled stepwise motion in polysilicon microstructures

Nanomechanical cantilever sensors have been emerging as a key device for real-time and label-free detection of various analytes ranging from gaseous to biological molecules. The major sensing principle is based on the analyte-induced surface stress, which makes a cantilever bend. In this letter, we present a membrane-type surface stress sensor (MSS), which is based on the piezoresistive read-out integrated in the sensor chip. The MSS is not a simple "cantilever," rather it consists of an "adsorbate membrane" suspended by four piezoresistive "sensing beams," composing a full Wheatstone bridge. The whole analyte-induced isotropic surface stress on the membrane is efficiently transduced to the piezoresistive beams as an amplified uniaxial stress. Evaluation of a prototype MSS used in the present experiments demonstrates a high sensitivity which is comparable with that of optical methods and a factor of more than 20 higher than that obtained with a standard piezoresistive cantilever. The finite element analyses indicate that changing dimensions of the membrane and beams can substantially increase the sensitivity further. Given the various conveniences and advantages of the integrated piezoresistive read-out, this platform is expected to open a new era of surface stress-based sensing.

Nanomechanical membrane-type surface stress sensor.

This paper presents a surface micromachined polysilicon actuator which employs an electrostatic driven Scratch Drive Actuator (SDA) to generate a force that can move an extemal object. The micro actuator consists of the SDA, a link frame and a buckling beam. Using this structure, generated forces of the SDA as a function of applied pulse peak voltages were measured. A typical generated force was 63 pN at +112 V pulse peak voltage. Indirect and direct methods of obtaining physical work from the micro actuator are presented. The actuator could lift 1 mg weight up at a height of about 100 pm from the wafer surface by the direct method. The total energy of this work was 1 nJ.

A quantitative analysis of Scratch Drive Actuator using buckling motion

This paper describes the characterization and application of electrically insulated conductive tips mounted on a cantilever for use in an atomic force microscope and operated in liquid. These multifunctional probes were microfabricated and designed for measurements on biological samples in buffer solution, but they can also be employed for electrochemical applications, in particular scanning electrochemical microscopy. The silicon nitride based cantilevers had a spring constant ≤0.1 N m-1 and a conductive tip, which was insulated except at the apex. The conductive core of the tip consisted of a metal, e.g. platinum silicide, and exhibited a typical radius of 15 nm. The mechanical and electrical characterization of the probe is presented and discussed. First measurements on the hexagonally packed intermediate layer of Deinococcus radiodurans demonstrated the possibility to adjust the image contrast by applying a voltage between a support and the conductive tip and to measure variations of less than 1 pA in faradaic current with a lateral resolution of 7.8 nm. © 2005 IOP Publishing Ltd.

https://iopscience.iop.org/article/10.1088/0957-4484/16/8/001/pdf

Terunobu Akiyama

Papers

Scratch drive actuator with mechanical links for self-assembly of three-dimensional MEMS

Controlled stepwise motion in polysilicon microstructures

Nanomechanical membrane-type surface stress sensor.

A quantitative analysis of Scratch Drive Actuator using buckling motion

Assessment of insulated conductive cantilevers for biology and electrochemistry