Everything about Microspheres
RSS feed
  • 12th International Symposium on Particle Image Velcoimetry

    Particle Image Velocimetry and Seeding Particles

    I recently attended the 12th International Symposium on Particle Image Velocimetry in Busan, Korea on behalf of Cospheric, a company that specializes in precision microspheres. With the hope of learning more about seeding particles involved in PIV research and what advancements in microsphere technology would benefit the work being done in flow visualization. Through conversations with many attendees I was able to gather information on some of the important factors involved in tracer particle and their ideal capabilities. An interesting addition to seeding particles brought up by several individuals was temperature sensitive spheres which could potentially provide temperature field information.

    Below is an example of neutrally buoyant microspheres which are used as flow tracers in PIV applications.

    Fluorescent Red Polyethylene Microspheres

    The venue, Haeundae Grand Hotel, was spectacular with multiple large halls available for the over 200 presentations. The surrounding city was a maze of markets and skyscrapers nestled between the mountains and coast. Wonderful weather graced us, even rivaling that of Santa Barbara. Which was not something I had considered possible. I had the pleasure and displeasure of trying many unique foods. With bibimbap from a shop near the beach and shrimp dumplings from a small business steeped in the steam used to cook their dumplings being definite highlights. While the eel which I am still unsure whether was cooked or not falling on the other side of the spectrum. I am still processing the wealth of information from ISPIV 2017 and will express my conclusions as it manages to leak from my head.

  • Use of Polyethylene Spheres for Analyzing Microplastic Transport in Correlation with Earthworm Presence

    Work by Matthias C. Rillig, Lisa Ziersch, and Stefan Hempel at Freie Universität and Brandenburg Institute of Advanced Biodiversity Research in Berlin has been published in an article titled Microplastic transport in soil by earthworms. This article investigates earthworms effect on microplastic movement into subsurface soil layers.

    Polyethylene Microplastic

    With the increase in plastic usage in recent decades the issue of how this discarded plastic will affect marine environments has been studied extensively. However, effects of microplastics on soil environments have not been tested to the same extent. Scientists have begun testing microplastic movement into lower soil layers by analyzing how differing sized polyethylene beads moved in a 21-day period with and without earthworm facilitation.

    The experiment was designed to confirm the assumption that earthworms would aid in particle movement. Results found earthworms to have a significant positive effect on transporting polyethylene particles from the soil surface. While particle size was also an important factor on the level of transportation into subsurface environments. With polyethylene spheres in the size range 710-850um being significantly more likely to move into the lowest layer when earthworms were present.

    With this experiment showing the ability of earthworms to transport microplastics into subsurface layers more research needs to be done to determine the effects this may have on the soil environment and the worms themselves. Including the multitude of other organisms that could also facilitate similar transportation. As well as the possibilities of microplastics reaching ground water where problems similar to those realized in marine systems could occur.

  • Neutrally Buoyant in Water – Microspheres with Specific Gravity of 1g/cc

    Cospheric offers polymer microspheres with specific gravity of 1g/cc are specifically designed to match the density of water for optimal suspension of particles. Suspension of microspheres in water enables the visualization and characterization of fluid flow and testing the capability of devices to withstand particulate matter in the fluid stream, ensuring that microspheres do not settle and do not float on the surface.  Most of these polymer microspheres are at least moderately opaque and clearly visible in water, clear or translucent liquids.

    Many Colors are available in sizes from 10um up to 1180um,  of polyethylene microspheres are available with specific density of 1g/cc, designed for optimum suspension in water for fluid flow visualization.  Colors include Violet, Orange, Yellow, Fluorescent, Grey, Pink, Blue, and many fluorescent colors.

    600-710um violet PE microspheres250-300um ORANGE PE Microspheresblue microspheres 355-425um Yellow microspheresGrey Microspheres PE

  • FDA-Approved Microspheres

    What makes a microsphere FDA-approved?

    In order to tell whether the microsphere can be used in cosmetics, food, or medical devices it is important to look at the raw materials that are incorporated into the microsphere during manufacturing process.  For example, unpigmented or clear polyethylene microspheres supplied by Cospheric in sizes from 10 micron to 1000 micron meet the quality requirements of the US FDA as specified in 21 CFR 172.888 and 21 CFR 178.3720.  Specific grade of polyethylene used in manufacturing of these microspheres is  FDA-approved for food applications in chewing gum base, on cheese and raw fruits and vegetables, and as a defoamer in food.

    Color additives are subject to a strict system of approval under U.S. law (FD&C Act), sec. 721; 21 U.S.C. 379e. Color additive violations are a common reason for detaining imported cosmetic products offered for entry into this country. If a product contains a color additive, by law [FD&C Act, Sec. 721; 21 U.S.C. 379e; 21 CFR Parts 70 and 80] you must adhere to requirements for:

    • Approval. All color additives used in cosmetics (or any other FDA-regulated product) must be approved by FDA. There must be a regulation specifically addressing a substance’s use as a color additive, specifications, and restrictions.
    • Certification. In addition to approval, a number of color additives must be batch certified by FDA if they are to be used in cosmetics (or any other FDA-regulated product) marketed in the U.S.
    • Identity and specifications. All color additives must meet the requirements for identity and specifications stated in the Code of Federal Regulations (CFR).
    • Use and restrictions. Color additives may be used only for the intended uses stated in the regulations that pertain to them. The regulations also specify other restrictions for certain colors, such as the maximum permissible concentration in the finished product.

    Continue reading “FDA-Approved Microspheres” »

  • Phosphorescent Microspheres – Long Afterglow Particles

    Phosphorecent Beads - Yellow Green Afterglow Spheres

    Phosphorecent Beads - Yellow Green Afterglow

    Phosphorescent microspheres in particle sizes 10 to 600 microns are now available from Cospheric LLC. These phosphorescent particles are 90% spherical and appear to be off-white under ordinary daylight or regular room illumination.  However, when the lights are turned off these phosphorescent particles exhibit phosphorescent yellow-green after-glow.

    The spheres have tight particle size distributions and are > 90% within size range.  Polymer spheres that incorporate proprietary phosphorescent ingredient have a melting point of 115°C , and are mechanically stable past 90°C.  Phosphorescent beads are also inert in most solvents.

    Phosphorescent Decay CurveIntensity of Phosphorescent Afterglow:

    Intensity according to DIN 67510-1

    800 mcd/m2 at 1 minute
    180 mcd/m2 at 5 minutes
    90 mcd/m2 at 10 minutes
    12 mcd/m2 at 1 hour
    5 mcd/m2 at 2 hours

    Excitation and Phosphorescent Emission Curve:
    Excitation and Emission Spectra