Large Polystyrene Spheres Available
High Quality precision Large Polystyrene Spheres now available.
Sizes of 2mm and 4.4mm.
Having a density of 1.05g/cc size ranges as narrow as CV=0.2% these are excellent for research applications
Glass Microspheres Used in Studying Self-Cleaning Gecko-Inspired Adhesives
Researchers from Carnegie Melon University and Karlsruhe Institute of Technology have recently published an article in Journal of the Royal Society titled Staying Sticky: Contact Self-Cleaning of Gecko-Inspired Adhesives that presents the first gecko-inspired adhesive that matches both the attachment and self-cleaning properties of gecko’s foot on a smooth surface.
Using glass microspheres to simulate contamination the scientists created a synthetic gecko adhesive that could self-clean and recover lost adhesion. Real world applications of self-cleaning adhesives are reusable adhesive tapes, clothing, medical adhesives (bandages) and pick-and-place robots, among others.
Everyday challenge with traditional adhesives is that they loose their stickiness once contaminated. Geckos have been intriguing researchers for decades because of their unique and striking capability to maintain the stickiness of their toes through contact self-cleaning. They can travel up the walls and ceilings in a wide variety of “dirty” settings retaining adhesion.
Upon experimentation, scientists discovered that the critical variable is the relative size of microfibers that make up the adhesive compared to the diameter of contaminant particles. Glass microspheres were used in diameters from 3 to 215microns. Glass microspheres were packed in air and used as supplied. Contamination of the samples was achieved by brining each sample in contact with a monolayer of glass microspheres with specific speeds under predetermined compressive loads. The cleaning process involved a load-drag-unload procedure.
Best self-cleaning results were obtained with the largest contaminants (glass microspheres), with the size of the adhesive fiber much smaller than the contaminating particle. This information is important to know when designing self-cleaning adhesives—make the adhesive fibers much smaller for improved adhesion recovery. This cleaning mechanism requires unloading particles by dragging. The other extreme of contaminating microspheres being much smaller than the adhesive fibers has advantages in some situations, even though it works by a different mechanism. Smaller microspheres tended to become embedded into the adhesive material. Particle embedding is a temporary cleaning process but might be sufficient in some applications.
Silica Nanospheres as Photonic Nanostructure Found in the ‘Disco’ Clam Ctennoides Ales
Scientists from UC Berkeley have recently discovered that a strange naturally occurring bright display of the ‘disco’ or ‘electric’ clam Ctenoides ales is actually a photonic display created by a layer of silica nanospheres. The display functions solely by reflecting light.
An article was published in the Journal of The Royal Society titled “A Dynamic Broadband Reflector Built from Microscopic Silica Spheres in the ‘Disco’ Clam Ctenoides Ales“, where the researchers shared their findings.
Laboratory elemental analysis of the reflective nanospheres showed that they are indeed composed of amorphous silica. Both the outer shells and the cores are composed of silica. Silica nanospheres are secreted by the animal and used as a light scattering structure in a behavior modulated reflective photonic display.
The measurements show that the diameter of the silica nanospheres is at around 300nanometers, an optimal particle size for scattering visible light, especially the shorter blue-green wavelengths of 400-500nm that predominate at 3-50m underwater, which is typically the clam’s habitat. In addition to the diameter, the highly organized packing structure of the nanospheres aid in the scattering of the visible light at the shorter wavelengths.
The display is so bright that it has been mistakenly thought of as bioluminescent, but the findings show that it is actually based on light scattered by photonic nanostructures.
Silica has a high index of refraction at n=1.43 at 589nm.
This study is extremely interesting to scientists in many different fields because it opens their minds up to many creative uses of silica nanospheres that have not been known before. The findings show a practical way to manipulate light in low light situations. Among its other advantages, silica, similar to glass, is a very durable material, with high melt point. Using silica nanospheres in tightly packed arrays to create photonic nanostructures seems like a great idea.
Highly precise and spherical silica nanospheres with narrow size distribution, diameters around 300nm and sphericity of greater than 99% in dry powder from can be purchased from CosphericNano—a new website specializing in precise silica nanospheres.
Deformable Silver Coated PMMA Microsphere Spacers
Silver Coated Glass Microspheres work well for increasing the conductivity of bond lines, but they lack the capability to deform when compressed to give increased conductive contact between the surfaces of the bond line. These newly released Silver Coated PMMA Microspheres offer the low weight deformable pmma cores, and 250nm thick silver coating for high conductivity.
Conductivity of this product has been measured at <0.5ohm per square with a 30% by volume preparation. Sizes available cover both the common 50 micron (45-53um) and 100 micron (90-106um) sizes and many others.
These spheres are perfect for producing anisotropic (only conductive in one direction) conductive bond lines.
Actual bond line thickness achieved will be a function of the assembly pressure and the size spheres selected.
In addition to being high conductive these silver coated PMMA is bio-compatible.
Reflective Billboard – Creative Outdoor Billboard for McDonald’s
What a creative alternative to power-hungry digital displays. This large outdoor billboard is totally environmentally friendly because compared to LCD and LED displays that run on electricity, this display takes no energy to run. This creative outdoor billboard is made with reflective tape, visible only when illuminated by headlights in the darkness, created by ad agency Cossette. To promote a local 24-hour McDonald’s in Canada, Cossette Vancouver designed this reflective billboard that’s only visible at night when cars pass by. By day, the billboard appears blank with no message, but at night, motorists driving along the highway reveal Mickey-D’s clever advertisement with their car headlights. Not only does this display save energy, it can be put anywhere, even in cities with strict requirements on flashing and lit displays.
Even though this particular display was made using reflective tape, many types of retroreflective media can be made by incorporating retroreflective microspheres in a variety of substances. Retroreflective Microspheres are made by applying a half-shell aluminum coating on solid barium titanate glass microspheres. The spheres hemispherically coated with a thin aluminum shell produce a bright retroreflective response directed back to the light source.