We get a lot of questions here. Questions
about contact angle; questions about our instrument products; questions
about shipping costs to Kalamazoo. Some questions we get a lot. So, this
month I will answer all of the most common ones. One of them may be
Which model measures contact angle?
They all do. From
to Model 790,
every one of our instruments can measure contact angle. However, as you
move up the product line, additional types of measurements (e.g.,
surface energy and surface tension) can also be made. A greater degree
of automation is also available on higher end models.
If I'm interested in basic wetting
properties, why do I need anything beyond the most basic system?
For static contact angle, Model 190 may be sufficient. However, by
moving to Model 200 or higher, you gain a number of surface energy
tools. By measuring contact angle using two or more liquids and then
calculating the surface energy, you can obtain a more comprehensive
picture of the surface properties. Likewise, by going with a more
automated system such as
you can measure advancing and receding contact angle, roll-off angle,
and contact angle hysteresis which offer an insight into surface
homogeneity with regard to both chemical as well as structural
Where are your instruments made?
Here in the USA.
How long have you been around?
Since 1961, which is longer than I've been around. We were
originally in Mountain Lakes, NJ and since 2011 have been at our new
facility in Succasunna, NJ.
Do you sell overseas?
About a third of our instruments are shipped to customers outside of
the United States. In many foreign regions we have sales agents who help
our customers locally before and after the sale.
Who invented the ramé-hart
That would be Dr. William A. Zisman who worked for the Naval
Research Lab (NRL) from the late 1930s into the 1960s. The first
ramé-hart contact angle goniometer was aptly named the NRL Contact Angle
Goniometer. More on Dr. Zisman here:
Dr. William A. Zisman
I used a ramé-hart instrument in
college some 25 years ago. Is that model still available?
You are likely referring to our ubiquitous Model 100-00 which we
made thousands of over a span of more than forty years. It used a
microscope for measuring and was a manual tool. We discontinued Model
100-00 some ten years ago because the level of precision and automation
that can be obtained from our current-generation camera-based
software-controlled tools is so far superior to the manual system, that
it's no longer a viable and competitive alternative to our current
Do you have an environmental chamber?
Yes. In fact, we now have a variety of chamber options for specific
tasks. Our standard
Environmental Chamber 100-07 offers temperature control up to 300°
C. For chilled environments, we have a
Peltier Environmental Chamber 100-30 which can be controlled down to
-50° C and at elevated temperatures up to 150° C. Our
Advanced Chamber 100-26-TH can control both humidity and
temperature. We now offer a
Hot Plate 100-33-HP and
Heated Environmental Cell 100-33, both can be controlled up to
300°C. To compare the different chamber options, see the product matrix
on this page:
ramé-hart Heated Environmental Cell
What kind of water should I use for
contact angle measurements?
Pure deionized water.
How do I know if it's pure?
The easiest way to check this, if you have Model 250 or higher with
DROPimage Advanced, is to simply measure the surface tension of the test
water. If it measures close to 72 mN/m, it's good. If it's significantly
lower, it could be contaminated. Clean your syringe thoroughly and try
What's the best way to see the
DROPimage software in action?
Short of having an instrument in front of you with someone to demo
it for you, the best way to see DROPimage in action is to
check out our video series on YouTube here:
Why should I buy from ramé-hart?
We were the first company in the world to make a production model
contact angle goniometer and we have over fifty years experience doing
so. We do nothing else - just contact angle, surface energy, surface
tension, and related surface measurements. Despite our extensive wealth
of experience, we continue to innovate and work hard to bring you the
best possible user experience. All of our instruments are highly modular
and upgradeable. We have the widest possible catalog of
accessories for common and more specialized tasks. We take quality
and customer service very seriously. Each day we work hard to earn your
business and keep you as a customer now and for the next fifty years.
I want to buy a contact angle
goniometer. How do I go about that?
First, check out our product matrix here
http://www.ramehart.com/goniometer.htm. Next, check out the
accessories. If you have any questions at all, call or
and we'd be happy to help you decide on the best model for your
application. When you are ready,
us again for a formal quotation for the model and accessories you've
decided on. Forward the quotation to your purchasing department so they
can prepare a purchase order.