Figure 2 shows that the Rhodamine B disappeared from all of the NANOPIGMY surfaces, with a self-cleaning pigment, at a faster rate than from the reference surfaces. The average level of Rhodamine remaining after 6 days was 3.78% for NANOPIGMY surfaces and 11.25% for the reference surfaces. To a first approximation, the NANOPIGMY surface was only 1/3 as discoloured after the six days of measurement.
If replicated over a longer timescale, this result would mean that an external render containing the NANOPIGMY self-cleaning pigment would only need to be cleaned at 1/3 the frequency of a standard render.
This reduction in cleaning means that the cost and the environmental impact of cleaning is significantly reduced by using the NANOPIGMY render.
The NanoPigmy project has taken this further by developing multi-functional pigments with two distinct properties, apart from colour, in a single material. This approach gives the pigment, and hence the ultimate product into which it is incorporated, a broader set of applications and the opportunity to deliver a wider set of benefits.
The combinations of additional properties that NANOPIGMY has targeted include the following:
- Thermal storage combined with anti-bacterial properties, for internal paints and partitions that could help control internal building temperatures and inhibit the growth of bacteria in hygiene-sensitive areas
- Thermal storage combined with self-cleaning properties, for external renders that could help control transmission of heat into a building and also reduce the need for external cleaning of heavyweight facades
- Low emissivity combined with anti-corrosion properties, for external paints and coatings that could help reduce heat transmission through steel façade panels and also lengthen the life of these panels
- Anti-bacterial combined with self-healing properties, for internal plastic components to maintain hygiene and to reduce the effect of damage to fixtures and fittings inside buildings.
These pigments have been developed under laboratory conditions, and are now being scaled-up to pilot production processes. The commercial effectiveness of these manufacturing challenges will not be known until the end of the project, but at this stage there are some promising technical results from small-scale demonstrations of the innovative pigments and the modified materials that they have been incorporated into.
The pigments have been tested on small demonstrator buildings on the outskirts of Madrid by Acciona, one of the project partners. Some of the preliminary results are reported here.