December 2010

Whenever I'm in a public setting and someone asks me what I do for a living I typically remain coy by answering that I'm in sales. When they press me for what I sell, I say scientific instruments. When they want to know what kind of scientific instruments, I let it out: "I sell goniometers." Inevitably the response is "What's a goniometer?" This answer I've got down pretty well - I hand them a business card which on the reverse is printed an image like the one below showing two sessile drops: one on a hydrophobic surface and the other on a hydrophilic surface. If they seem interested, I go on to give them a primer on basic wetting, surface energy, and surface tension.

If we make it that far, the next question is: "So what exactly do people use these goniometers for?" That's when I ask them to sit down. You see there is no short answer for this question.

This month's newsletter is dedicated to answering that question. And so, here is a list of 50 things people do with their ramé-hart goniometers (and tensiometers). Believe me, this is not a comprehensive list.

1. Chip makers (the silicone not potato variety) use contact angle to QC their wafers after they go through plasma and other cleaning processes.

2. A Midwest beer bottler uses their goniometer to measure the cleanliness of bottles after cleaning but prior to sticking the label on to ensure a good stick.

3. A QC tool to check cleanliness on disk drive platters during fabrication.

4. Contact lens manufacturers use contact angle as a QC tool during fabrication.

5. Understand the effects of a change in temperature on wetting.

6. Discover the impact a change in surface energy has on rubber latex films.

7. A maker of glass products studies wetting properties to develop coatings that are more thermally efficient.

8. Study evaporation by change in drop volume over time.

9. A manufacturer of LCD displays uses a goniometer to measure wetting on treated glass surfaces to ensure adhesion during the fabrication process.

10. Characterize the impact anodizing has on aluminum surfaces.

11. The provider of coatings uses contact angle to design processes used in the production of rainwear that lowers the surface energy of the product.

12. An electronics company uses contact angle to optimize surface treatments that lead to better adhesion of solder.

13. A paint company uses contact angle to help develop a paint that is superhydrophobic and thus is self-cleaning (e.g., Lotusan).

14. Quantify the impact a change in humidity has on wetting of polymer surfaces.

15. Use surface tension measurements to detect contamination of aqueous liquids.

16. A lab specializing in biomimicry uses advancing and receding contact angle measurements to make surfaces with lotus-leaf-like qualities.

17. Study the effects a change in roughness has on a surface.

18. Petroleum engineers use interfacial tension to study the oil/water interface under high pressure.

19. A plastics company uses wetting as a metric for developing plastic materials which have reduced wetting for applications such as shower curtains and raincoats.

20. Quantify the reduction in surface tension a particular surfactant has.

21. A cable supplier uses contact angle to develop surface treatments to prevent ice build-up on long-distance high-voltage power transmission lines.

22. A paint manufacturer uses contact angle to study the adhesion of their product on concrete surfaces.

23. Study the wettability of microbead suspension using contact angle hysteresis.

24. A large manufacturer of femcare products test tapes used on personal care products in an environmentally controlled condition to improve their stickiness while reducing the residue they leave behind.

25. Characterize the change in a sessile drop as it changes from a Cassie to a Wenzel state.

26. Gemologists use contact angle on diamonds and other gems to quantify purity and detect counterfeits.

27. Measure the hydrophobicity of a nanotextured surface.

28. An electronics manufacturer uses contact angle to maximize adherence of components to the molded plastic parts.

29. Watch the effects of electrocapillarity on charge-induced substrate.

30. A carpet maker uses contact angle to research ways to make their product more hydrophobic and less susceptible to fouling.

31. Study the wetting effects of lubricants (perflouoropolyether) on silicon wafer.

32. QC surface treatments on glass.

33. Study the surface tension of emulsions as they are modified.

34. A car parts company uses their goniometer to develop treatments that make rear view mirrors more hydrophobic and thus self-cleaning.

35. Lead frames go through an etching process. Contact angle is used to check the expected efficacy of the etching process so subsequent bonding processes will be successful.

36. A maker of pesticide uses a ramé-hart goniometer to measure surface energy of biomatter (e.g., leaves) to develop a pesticide product that has optimal wetting properties.

37. A consultant uses contact angle to improve surface cleanliness for a customer's photoresist bonding application.

38. A maker of commercial adhesives uses contact angle to develop an improved primer that will promote better bonding of their adhesive products.

39. Oxygen permeability of contact lenses can be studied using contact angle data.

40. A lab on the West Coast characterizes surface modifications using contact angle in order to develop a surface treatment for removing mold release agents.

41. Switchable wetting is studied on polyurethane coatings at a university in the South.

42. Scientist are using contact angle to develop non-fouling nanosurfaces.

43. A major dental supplier uses contact angle to improve adhesiveness of newly developed dental bonding agents.

44. Wetting studies used to understand argon plasma treatment for surface modification of polypropylene for medical applications.

45. Water repellency is improved on wood surfaces using hexamethyldisiloxane-plasma coatings. Contact angle is used to quantify the success of the coating process.

46. Improve biocompatibility of polymer-based medical devices.

47. Self-assembled monolayers (SAMS) are used to control the wetting properties of gold surfaces.

48. A chemical supplier uses surface tension values to ensure his customers that his product is pure and undiluted.

49. Study the effects lowered roughness levels have on Chemflex, a dental bonding product, and the impact it has on the release of fluoride.

50. A maker of solar panels is using contact angle to develop new coatings for a thin film product that will improve efficiency and reduce maintenance.

If your application does not appear on this list, please let me know what it is and I'll make sure it appears on Part 2 of this newsletter which will inevitably be published in the future.
 

All of us at ramé-hart instrument co. would like to wish you a happy and safe holiday season and a prosperous New Year. Thank you for your patronage and we look forward to being of service to you in 2011, our fiftieth year of continuous operation.