Apparatus[edit | edit source]

Microfluidics and Interfacial Transport Laboratory in Mechanical Engineering – Engineering Mechanics at MTU is home to a customized sessile drop contact angle measurement system. The setup the comprises of 3 major components: (1) optics and illumination subsystem, (2) sample environment and manipulation stage and (3) a microscope coupled to CCD camera. A Kodak medalist carousel projector is used as the light source. Köhler illumination is implemented using a lens array to produce a collimated beam of light with uniform intensity. The sample environment stage consists of a labjack (Thorlabs L200) mounted on a translation stage (Velmex AXY2509W) enabling X-Y-Z movement of the sample stage. The top of the sample environment stage consists of a copper block with four thermo-electric coolers (Marlow Industries DT12-6-01L). The temperature is controlled by varying the voltage across the coolers. A humidity enclosure is also available to mitigate droplet evaporation. A long distance microscope (Infinity K2/S) is coupled to a CCD camera (PULNIX TM-1325CL) for focusing and image acquisition. Images are captured on an IBM thinkpad T60 laptop using the EPIX XCAP software and the EPIX EL1DB framegrabber.

Droplets of a set volume can be deposited on the sample using a threaded syringe (Hamilton 81242) using a location controlled by the sample environment stage. The setup is capable of acquiring images with a spacial resolution as low as 5 per pixel and a temporal resolution as high as 10000 fps. Image processing and complementary mathematical modeling is necessary to determine the contact angle from the acquired images. A Young-Laplace fit to the edge detected liquid-air interface is extrapolated to the solid substrate and a contact angle is determined. Based on accuracy and time constraints, the values for the contact angle could be measured either using a drop analysis plug-in in the open source ImageJ program or a custom built code. The general technique to determine contact angles and the custom built code for image processing and analysis can be found at [1].

CA setup.png

Basic Tests[edit | edit source]

  1. Room temp CA
  2. near freezing temp (0 to 5 degrees C) CA
  3. movie showing freezing and how CA changes. Might be able to see some frost propagation.

Dynamic tilt clear test? Force to remove ice?

Location[edit | edit source]

MEEM 1001, MTU

Contact[edit | edit source]

Dr. Kishan Bellur ksbellur@mtu.edu

Page data
Published 2019
License CC-BY-SA-4.0
Impact Number of views to this page and its redirects. Updated once a month. Views by admins and bots are not counted. Multiple views during the same session are counted as one. 44
Issues Automatically detected page issues. Click on them to find out more. They may take some minutes to disappear after you fix them. No lead section, No main image
Cookies help us deliver our services. By using our services, you agree to our use of cookies.