Press Release
Article for the Hearing Review
15 April 2010
Head: Protect and revive
Intro: Today’s hearing instruments are increasingly miniature,
sophisticated... and fragile. AridionTM, a new liquid repellent
nano-coating from P2i, promises to transform standards of reliability by overcoming
the limitations of traditional liquid repellency approaches.
According to Hearing Industries Association data, the proportion of behind-the-ear (BTE) models sold increased from 57.3% in 2008 to 64.1% in 2009, comprising almost 1.7million units in total and reaching their highest-ever market share of 66.3% in the fourth quarter of 2009 [1].
But closer scrutiny of the figures also reveals that some 40% of the BTEs sold in 2009 are the latest, smallest, most discreet devices, and almost three quarters of those were receiver-in-canal (RIC) BTEs.
These figures reflect the growing aspiration, especially among younger users, for a hearing instrument that can be worn unobtrusively, and for more extended periods of time as an integral part of an active lifestyle.
However, as designs become smaller and more delicate, they are also increasingly difficult to protect. Hazards faced by hearing instruments are principally liquids, such as sweat, water and steam.
For example, in the January 2010 issue of Hearing Review, the Field Study on the Effect of Relative Humidity on Hearing Aid Receivers highlighted the extremely strong correlation between receiver problems and relative humidity between 60 and 90%.
Because RIC/BTE devices are delicate and contain expensive digital electronics, repair costs (to manufacturers via warranty failure, or users via accidental damage) are potentially very high, especially given the current trend towards wearing binaural devices (one for each ear).
What’s required, therefore, is a means of protecting the delicate componentry of hearing aids against the effect of aqueous and oleous (e.g. cerumen) contaminants.
Overcoming the limits of traditional approaches
Traditional ways of protecting the delicate electronics in hearing instruments
have involved the use of spray or dip applied coatings, but three limitations
detract from their appeal:
- Traditional protection is applied to individual components. After assembly, not all of the instrument will be protected equally.
- Spray and dip coatings are not durable and will rub off over time.
- Spray and dip coatings can be too thick to protect fine-tolerance acoustic components without affecting their performance.
AridionTM technology by P2i overcomes these limitations in a new and very different way. Plasmas [2] have long been known for their use in modifying the surface properties of materials [3]. AridionTM uses a special ionized gas (plasma), created in a vacuum chamber, to apply a pinhole-free protective polymer layer over the entire surface of a finished, fully-constructed hearing instrument. This layer is nanoscopically thin, but lowers the surface energy significantly so that when liquids come into contact with it, they form beads and simply roll off.
The way AridionTM treats finished articles, and readily penetrates their complex structures, is a step-change improvement upon traditional coatings. This is because the patented technology works at a pressure régime that allows fully penetration of the complex device, whilst the energised gas allows durable attachment to the plastics, metals and rubbers from which the product is constructed. This results in total device protection at the nano scale.
Improved reliability? No sweat...
Improved reliability has been demonstrated by P2i in the industry standard
sweat test, in which a hearing instrument placed on a prosthetic ear
is exposed to continual drops of a sweat solution for several days.
As before/after images show, no visible corrosion occurs in the AridionTM protected device after the sweat test; while visible corrosion is apparent in the uncoated sample. In tests with multiple samples, 100% of the AridionTM protected products pass while 80% of the uncoated products fail.
Ensuring longer-lasting performance
Because the AridionTM
nano-coating establishes permanent molecular bonds with the surface substrate,
it is much more durable and robust than traditional approaches. P2i's tests show that AridionTM is five times more durable than traditional coatings, being able to maintain an effective degree of water repellency for 600 abrasion cycles - uncoated samples lose their efficacy after just 100 cycles. Plus the strong bonding means the coating will not leach away.
Importantly for increasingly miniature devices, the AridionTM coating does not affect the performance of acoustic components in the same way as traditional approaches. It is one thousand times thinner than a human hair, making it acoustically transparent and imperceptible to users.
Conclusions
When complete hearing instruments are treated using the AridionTM process,
they achieve much stronger resistance to liquids than would be possible
by assembling components individually treated using alternative techniques.
The resulting improved product reliability is likely to decrease the
number of repairs required per unit, saving money, time and frustration
for manufacturers, dispensers and end users alike.
Author biog
Stephen Coulson, PhD, is the Chief Technical Officer of P2i.
Stephen invented the P2i technology while carrying out his PhD at Durham University on 'Liquid repellent surfaces'. He was consequently employed by the MoD to set up a plasma capability and further scale-up the patented technology for industrial applications. In 2001, Stephen moved into project managing the UK Nuclear Biological and Chemical clothing programme, but continued to exploit the plasma technology for a range of commercial applications. Stephen was the founding member of P2i when it was formed in January 2004 and has more than a decade's experience in advanced material sciences and plasma processing.
References
- HIA Hearing Aid Monthly Sales Statistics
- A. Grill, Cold Plasma Materials Fabrication: From Fundamentals to Applications, Wiley, (1994).
- H. Biederman, Plasma Polymer Films, Imperial College Press, (2004).
NOTES FOR EDITORS
About P2i
P2i is the world leader in liquid repellent
nano-coating technology. We make good products great by applying innovative
science. Our revolutionary technology enables our customers to improve
the performance of their products and protect them from the effects
of water and all other liquids. This builds value by commanding premium
prices and/or reducing costs.
P2i Ltd was established in 2004 to commercialise liquid-repellent treatments developed by the UK's Ministry of Defence. Now on a commercial scale and in production in factories world-wide, P2i's patented process has been successfully applied to a wide range of products in a number of markets including performance textiles, filtration and bio-consumables.
Corporate enquiries to:
Tel: +44 (0)1235 833100
Fax: +44 (0)1235 861214
Email: info@p2i.com
How P2i's technology works
P2i's technology works by applying a nanometre-thick polymer layer over the entire surface of a product. Using an ionised gas (plasma) this layer is molecularly bound to the surface and will not leach away. The process confers superior oil and water repellency by reducing the surface energy to ultra-low levels - down
to one third that of PTFE (polytetrafluoroethylene).