Santa Barbara, CA (PressExposure) April 21, 2009 -- Co-founders of Cospheric (http://www.cospheric.net), a microtechnology company based in Santa Barbara, CA, developed a real-time reliable technique for measuring electrostatic charge on microspheres. The technique involves creating a monolayer of microspheres arranged in a proprietary containment microstructure with each sphere separated from its neighbors, which allows precise measurement of electrostatic charge on large quantity of microspheres without allowing sphere-to-sphere interactions. The electrostatic charge on microspheres is calculated by observing movement of spheres in response to electric field. This technique is suitable for glass microspheres, polymer microspheres, ceramic microspheres, solid and hollow microspheres, as well as any microparticles.
Electrostatic charge (also known as triboelectric charge) on microparticles and microspheres have been of interest to scientists in chemical, pharmaceutical, cosmetic, drug delivery, displays and other industries for many years. Until recently there were no reliable techniques to measure or quantify electrostatic charge on microparticles, with too many uncontrolled variables the measurements were inconsistent. As a result scientists were treating charging as a black box process, performing the experiments blindly as trial and error. With Cosphericâs advances in microsphere manufacturing, techniques have been developed that promise not only to quantify the charge on microspheres, but to control the charge in the manufacturing process.
The most basic and most critical factor that needs to be controlled in order to obtain a reliable charge measurement is environmental. Since moisture from the air will form static dissipative coatings on all surfaces, charges will always be lower at high humidity. Proper techniques for handling microparticles are also very important. Electrostatic surface charge is acquired every time two materials come together: when microparticles are being collected, sieved, sampled, put in a bag, touched with a spatula, put on a glass microscope slide. Each of these processes adds or changes electrostatic charges. The solution is to neutralize all those acquired surface charges after the sample has been prepared and ready for testing.
The most difficult to control factor comes from the fact that even properly sampled and conditioned microspheres interact and transfer charges to each other. The challenge is finding a way to separate and measure individual microspheres while still getting data representative of billions of microparticles. Cosphericâs measurement technique achieves this by implementing a containment structure that easily and efficiently separates microspheres from each other but still allows observation of each individual sphere.
âFor the past seven years we have been manufacturing high-tolerance microspheres for digital display industry, where polarity and quantity of charge are critical for the display performance. We are very excited to have a real-time reliable solution to measure charges on spheres, which allows us to bring even better value to our customers,â says Brian Gobrogge, CEO and co-founder of Cospheric.
Armed with a fast and reliable technique for measuring electrostatic charge, engineers at Cospheric are able to do controlled experiments and tune their manufacturing process to produce microspheres and coatings of desired charge based on customerâs needs and specifications.
For more details on Cosphericâs R&D and Manufacturing can be found at http://www.cospheric.net.