Avoid nano no-no's
June 1st 2008

With all the hype surrounding nanotechnology products,Brent Dunleavey, MD of Radal Technology, takes a look at the facts behind the terminology and examines how nanotechnology coatings can contribute to the cleaning and hygiene industry

When we see advertising extolling the virtues 'Green Environmentally Friendly Nano Coatings' or hear the term 'nanotechnology' referred to in the media, perhaps many of us think:What on earth is it all about? The label 'nanotechnology' is an all encompassing term which may be applicable to a multitude of markets and market sectors. In the cleaning industry this label is more correctly best described as 'nano coating technology'.The term 'nano' is derived from Greek meaning small, and is a term widely used in engineering terms to measure values (such as electric current nA), or in the case of nano coatings – dimensions in billionths of a metre (nM).

The basic concept of all nano coatings is to 'engineer' an invisible barrier on any given surface (normally referred to as the 'substrate') and alter its inherent properties to something that we require.Good examples of this may be to make an otherwise difficult surface easier and quicker to clean, easier to remove graffiti or perhaps add an antibacterial property to enhance infection control measures.

A number of nano products have recently been introduced to the cleaning industry – but what are they and what do they do? In the case of products like RadaGlass for example, the product consists of non-particulant Si-O2 in liquid suspension. Essentially, it is a Liquid Glass Nano Layering Technology which can be applied to all surfaces (including glass, ceramics, metals, fabrics, stone, plastics and food packaging) by spray or wipe. Different formulations are available – designed for specific surfaces or substrates. Porous surfaces such as stone,wood, textiles and carpets are water based to allow simple application using an industrial spray technique. For hard or nonporous surfaces such as glass, ceramic, plastics and metals an alcohol based formulation eases application through evaporation.

The subsequent glass nano coating is invisible to the naked eye (100nM thick or 500 times thinner than a human hair) and does not change the appearance or texture of the surface.The coating is totally food safe, highly durable, flexible (200 per cent) and heat tolerant between -100°C to 450°C. Perhaps the most interesting characteristic is that the coating is super-phobic – which means that it rejects all soiling agents and can withstand solvents,most acids up to 0.5 pH and most alkalis up to 12.5 pH. In addition, treated surfaces become 'bio-static' through ionic exchange – which creates an environment which does not support bacterial growth.Some manufacturers have designed antibacterial variants which together with the inherent anti-microbial properties prevent bacteria gaining a foothold on any treated surface.

Once the liquid glass has been applied by spray or wipe, washbasins and stainless steel/ceramic surfaces can be used immediately, but full polymerisation will take up to 24 hours.During application, the polymerisation process and throughout its life, the coating is odourless, mucosa friendly, UV stable and food safe.Some manufacturers claim that the 'Professional Series'products will last up to five years between applications dependant on wear and tear. If the product ever needs to be re-applied, it is simply a matter of cleaning and re-coating the surface.There is no costly stripping and reapplication programme.

The treated surfaces can then be termed 'easy clean'. Due to the super-phobic nature of the nano coating, soiling agents cannot adhere to the surface and are easily and quickly removed using high dilution environmentally 'green' chemicals to leave a dry, smear free finish.

Research carried out to compare average cleaning times between a treated and an untreated washroom over one week cycle suggest that cleaning times can be reduced by as much as 20 per cent.

As with all things, the less scrupulous vendor jumps on the bandwagon whenever new and innovative products are brought to market. It is well worth ensuring that products marketed under the nanotechnology banner are indeed particle free products.Many products contain potentially dangerous nano particles such as carbon nano tubes which are used to repel soiling in some coatings and may be potentially problematic if inhaled, or aluminium which it is believed can migrate within the human body. In order to be sure that the nano coating is manufactured to the highest standard and is not mis-labelled or mis-sold, it is sensible to consult the vendor about any third party certification that may exist to back up any claims for the products in regard to food safety, and non-toxicity and of course its impact on the environment.

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