Electrohydrodynamics and dielectrophoresis in microsystems: scaling laws

نویسندگان

  • A Castellanos
  • A Ramos
  • A González
  • N G Green
  • H Morgan
چکیده

The movement and behaviour of particles suspended in aqueous solutions subjected to non-uniform ac electric fields is examined. The ac electric fields induce movement of polarizable particles, a phenomenon known as dielectrophoresis. The high strength electric fields that are often used in separation systems can give rise to fluid motion, which in turn results in a viscous drag on the particle. The electric field generates heat, leading to volume forces in the liquid. Gradients in conductivity and permittivity give rise to electrothermal forces and gradients in mass density to buoyancy. In addition, non-uniform ac electric fields produce forces on the induced charges in the diffuse double layer on the electrodes. This causes a steady fluid motion termed ac electro-osmosis. The effects of Brownian motion are also discussed in this context. The orders of magnitude of the various forces experienced by a particle in a model microelectrode system are estimated. The results are discussed in relation to experiments and the relative influence of each type of force is described.

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

منابع مشابه

Hybrid electrokinetics for separation, mixing, and concentration of colloidal particles.

The advent of nanotechnology has facilitated the preparation of colloidal particles with adjustable sizes and the control of their size-dependent properties. Physical manipulation, such as separation, mixing, and concentration, of these colloidal particles represents an essential step for fully utilizing their potential in a wide spectrum of nanotechnology applications. In this study, we invest...

متن کامل

Dielectrophoresis and electrohydrodynamics-mediated fluidic assembly of silicon resistors

In this letter, we present techniques, utilizing dielectrophoresis and electrohydrodynamics, which can be used for assembling single-crystal silicon devices suspended in a solution onto a binding site on a heterogeneous substrate. Silicon resistors with gold/chromium layers located at the end of the resistors and silicon blocks without metal were fabricated on bonded and etched-backed silicon-o...

متن کامل

Electrical forces for microscale cell manipulation.

Electrical forces for manipulating cells at the microscale include electrophoresis and dielectrophoresis. Electrophoretic forces arise from the interaction of a cell's charge and an electric field, whereas dielectrophoresis arises from a cell's polarizability. Both forces can be used to create microsystems that separate cell mixtures into its component cell types or act as electrical "handles" ...

متن کامل

Towards Single Molecule Manipulation with Dielectrophoresis Using Nanoelectrodes

We present measurements of the scaling of the dielectrophoresis force with electrode size and particle size, in order to determine the ultimate size limits for dielectrophoresis at the nanoscale. To demonstrate the feasibility of nano-manipulation we present studies on the dielectrophoretic manipulation of DNA with microfabricated electrodes using RF electric fields. We find that DNA undergoes ...

متن کامل

Optimization of Liquid DiElectroPhoresis (LDEP) Digital Microfluidic Transduction for Biomedical Applications

Digital microfluidic has recently been under intensive study, as an effective method to carry out liquid manipulation in Lab-On-a-Chip (LOC) systems. Among droplet actuation forces, ElectroWetting on Dielectric (EWOD) and Liquid DiElectroPhoresis (LDEP) are powerful tools, used in many LOC platforms. Such digital microfluidic transductions do not require integration of complex mechanical compon...

متن کامل

ذخیره در منابع من


  با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

عنوان ژورنال:

دوره   شماره 

صفحات  -

تاریخ انتشار 2003