Invited talk at Conference Dubai Nanotech 2013. Nanoscale-based Concepts for Innovative and Eco-Sustainable Constructive Materials: Challenges and Opportunities for Energy and Environment Applications. Economic impact of Nanotechnology. 1-Development of smart coatings for window IR control 2-Flexible smart multilayers for coloration & shading 3-Solar Tiles - photovoltaics thin films integrated on roof tiles and ceramic facades 4-Development of novel asphalt pavements with photocatalytic ability (with self-cleaning and pollution reduction functions)

1. Vasco Teixeira
Vasco Teixeira, Joaquim Carneiro
Department of Physics, University of Minho
Azurém Campus, 4800-058 Guimarães, PORTUGAL
vasco@fisica.uminho.pt
Nanoscale-based Concepts for Innovative and Eco-
Sustainable Constructive Materials:
Challenges and Opportunities for Energy and Environment Applications
Nanotech Dubai 2103
28-30 Oct. 2013

2. Vasco Teixeira
Outline
Nanotechnology
Construction
Industry
Definition of nanotechnology and nanomaterials
Economic impact of Nanotechnology
Integration of nanomaterial’s in construction industry: some examples
1-Development of smart coatings for window IR control
2-Flexible smart multilayers for coloration & shading
3-Solar Tiles - photovoltaics thin films integrated on roof tiles and
ceramic facades
4-Development of novel asphalt pavements with photocatalytic
ability (with self-cleaning and pollution reduction functions)
Project´s overview:
Conclusions

3. Vasco Teixeira
Innovative nanoscale coating architectures for functional
decorative and smart surfaces
GRF- Functional Coatings Group
500 1000 1500 2000 2500
0
10
20
30
40
50
70ºC
Transmittance(%)
Wavelength (nm)
10ºC
a
)
b
)

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Nanotechnology
A definition of Nanotechnology was presented in 1981
by Drexler, as being the fabrication of several structures
with dimensions and precision between 0.1 and 100 nm.
 human hair diameter ~80,000 nm DNA double helix diameter = 2 nm
Top DownBottom Up
Mincor TX TT

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Nanocrystalinne materials: % atoms in grain
boundaries
HRTEM image of a region of
nanocrystalline palladium
Unifying features
-synthetic materials with modulated structures in 0 to 3
dimensions.
-size constraint (“confinement”) <100nm in at least one
dimension.
-significant volume fraction (>1%) of interfaces.
As the grain size decreases to the nanometer range, there is a significant
increase in the volume fraction of grain boundaries or interfaces.

6. Vasco Teixeira
Nanotechnology
Available forecasts suggest a global market for nanotechnology
products in the range of USD 150-3100 billion in the coming
years, while some 2 million new jobs could be created.
The global distribution of R&D investments, publications and
patents indicate that nanotechnology related research and
development activities are concentrated in a few countries and
regions of the world.
The United States dominates in this context with regions in the San
Francisco, Boston, New York and Los Angeles area, followed by
Japan and some of the larger EU countries (Germany, France and the
United Kingdom).
The rapid entry of other countries such as Korea, India and
especially China should also be highlighted.
OECD - Organisation for Economic Co-operation and Development, STI WORKING PAPER 2009/7
Report Nanotechnology OECD

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Forecast 2015:
• Annual growth of 10-15%
• Nanotech driven total
market volume >750 bn Euro
Nanotechnology: Market potential

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Examples of Companies already
using Nanotechnology

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Nanocoatings are opening new market opportunities in
the global surface coatings arena, offering new
applications in various sectors
Revenues from anti-microbial, easy-clean and self-
cleaning nanocoatings were approximately US$ 764
million in 2010
Main markets are in construction and exterior protection
(mainly in anti-weathering coatings and glazing) and
interior household protection for surfaces (easy clean
and anti-microbial)
Revenues expected: approx. US$ 2117 million in 2015
The world market for nanocoatings

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Introduction: Construction Industry
 60% of global industrial waste is from the
construction and demolition of buildings
 60% of electrical use in developed countries
is by buildings
 40% of total energy consumed is by buildings
How to integrate nanomaterial’s in construction
industry?
• Task #1: Building energy savings
• Task #2: Road pavements
Due to a constant market push towards
more durable, more sustainable and
more cheap products, products for the
construction industry are option for
continuous research and development.

11. Vasco Teixeira
Schematic overview of a typical house indicating where
nanoproducts could be found
"Einsatz von Nanotechnologien in Architektur und Bauwesen" published by HA Hessen Agentur 2007, sources: Schrag GmbH VDI TZ
Nanoproducts in Construction Sector

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Overview – nanorelated areas and their relevance
for the construction sector (after Andersen and Molin 2007)

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Overview – nanorelated areas and their relevance for
the construction sector - cont.(after Andersen and Molin 2007)

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Nanosilica and nanotitania in construction
Cement and Concrete • Nanosilica and clinker used to increase
densification and hence mechanical
properties and durability of cementitious
materials
• Service life can be doubled through the use
of nano-additive viscosity enhancers which
reduces diffusion of harmful agents in
concrete
• Photocatalytic TiO2 (nanotitania)
nanoparticles added to concrete to reduce
carbon monoxide and NOx emissions on
roadways

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-Rolling water drops
act as “mini-wipers“
-no adhering water drops => no
evaporation residues, “spots”
-self-cleaning
q << 90° hydrophilic surface
q= 120° hydrophobic surface (e.g. Teflon)
sliding drops, no roll off
q  180° ultra-hydrophobic surface
roll off angle  0°
(flat) hydrophobic surface
90° <= intrinsic contact
angle qi <=120°
hydrophobic surface combined
with specific surface nano-roughness
contact angle q 180°
Ultra-hydrophobic surfaces: “Self-cleaning effect”
Smart nanocoatings - Self-cleaning & anti-dirt surfaces
“Study of the deposition parameters and Fe-dopant effect in the photocatalytic activity of
TiO2 films prepared by dc reactive magnetron sputtering”, J.O. Carneiro, V. Teixeira, A.
Portinha, L. Dupák, A. Magalhães and P. Coutinho, Vacuum, Vol 78, 2005, p.37-46

16. Vasco Teixeira
When a photon impinges a
semiconductor with energy equal to
or higher than the respective band
gap, an electron is promoted from the
valence to the conduction band,
creating a hole in the valence band.
In semiconductors, a portion of these
photo-excited electron/hole (e-/h+)
pairs diffuse to the surface of the
catalytic particle and electron/hole
pairs are trapped at the surface.
These (e-/h+) pairs take part in
chemical reactions with the adsorbed
donor or acceptor molecules.
Photocatalytic Products: Titanium Dioxide (TiO2)
 TiO2 based materials has been the target of several research works due to its powerful oxidation
strength, chemical stability, non-toxic properties and availability.

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Photocatalytic Products: market
Taking into account that, within
civil construction market,
photocatalytic products are
mainly used for building
facades its application on other
constructive structures with
large surface areas such as
road pavements will contribute
to the enlargement of the
overall market share.
 The field of construction and building industry was identified as an important market for
the use of photocatalytic products since they can be applied to reduce building facades
maintenance costs and pollution effects, particularly important in metropolis with high
population density.
 In fact, the field of construction and building materials holds the largest market share
(about 87%) in what concerns photocatalytic products.
Source: BCC Research

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Coatings - Inorganic
conventional
glass
self-cleaning
glass
Self-cleaning glass
TiO2 coating
glass
transparent TiO2
Self-cleaning & anti-dirt surfaces
 The advantages of self-cleaning coatings range from reducing maintenance
costs and prevention of snow and ice build-up, to protection from environmental
pollution.

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PLEXIGLAS SOUNDSTOP® with
Photocatalytic Coating
Some examples (self-cleaning and
pollution reduction)
UMinho - ceramic samples with
Photocatalytic Surfaces
After UV
radiation
UMinho - water purification
Nano-Photocatalysis
Using TiO2 photocatalytic material on roadway for
pollution reduction

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Solar control coatings are a technology with growing interest due to the
necessity of improving the energy efficiency of buildings avoiding
excessive energy consumption with cooling systems on summer.
Thermochromics materials - smart
coatings for window IR control
VO2(M) is being considered as
a potential candidate for
application in smart windows
with active solar control for
energy savings
I.P. Parkin and T.D. Manning, Journal of Chemical Education 83 (2006) 393-400

21. Vasco Teixeira
Thermochromic coatings: V0.97W0.03O2
0 10 20 30 40 50 60 70 80
0
5
10
15
20
25
30
35
40
45
50
Heating
Cooling
Transmittance(%)
Temperature ºC
Ts = 40ºC
=2.5 m
500 1000 1500 2000 2500
0
10
20
30
40
50
70ºC
Transmittance(%)
Wavelength (nm)
10ºC
Thermal control of buidings (smart
windows)
W doped films with different
switching temperatures (e.g. 20 to
60ºC) and max. transmittance over
40%, in the visible, can be easily
obtained by reactive magnetron
sputtering.
Semiconductor
Monoclinic phase
Metallic
Tetragonal phase
Reversible
APPLICATIONS:
- optical and electrical switching devices
- light detectors
- temperature sensors
- microbatteries
40ºC

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 Nanoparticles enhance
physical and aesthetic qualities
 Hard, durable finish
 Excellent water resistance
 Self-Cleaning ability
 Stain blocking and other
properties
 Thermochromic inks
Paints
Thermochromic nanobased inks
Bituminous road pavements
Thermochromic nanobased inks
Sensorial ink developed at
UMinho

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Innovative shading devices
Electrochromic Coatings / Switchable Glasses
Switch!!
Carl M. Lampert, Materials Today,
March 2004 p.28-35
Device in operation
UMinho
Flexible Device in operation
EU FP7 Innoshade Project
H. N. Cui , M. F. Costa, V. Teixeira, I. Porqueras, E. Bertran,
Electrochromic coatings for smart windows, Surface Science, Vol.
532(2003) 1127-1131.

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Building Integrated Photovoltaics (BIPVs)
• Depositing directly on tiles and ceramic
facades the solar cell based in silicon.
• Predominant photovoltaic material is
silicon, but an emerging technology
involves the use of dye-sensitized solar
cells with TiO2 nanoparticles .
• Large surface area of TiO2 nanoparticles
greatly increases photovoltaic efficiency
• Also has potential for lower material and
processing costs relative to conventional
solar cells.
 With the development of nanotechnology in various areas of materials
science, the possibility of more efficient solar conversion by employing
nanostructured components in thin film solar cells can be possible.

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UMinho Project: Photocatalytic Asphalt Mixtures
The modified asphaltic mixtures should be able
to:
 Degrade adsorbed organic compounds and
reduce the concentration of pollutants in air
without loosing any of the initial mechanical
and physical characteristics of the road
pavement
Strategies:
 Surface deposition (by spraying) of TiO2
nanoparticles
 Addition of TiO2 nanoparticles by volume
incorporation
Production of new Asphalt Mixtures by using TiO2 Nanoparticles

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Photocatalytic Asphalt Mixtures
Development of innovative
PHOTOCATALYTIC asphalt
mixtures by using TiO2
nanoparticles
Two methods used in the
preparation of photocatalytic
asphalt mixtures
J.O. Carneiro et al. / Construction and Building
Materials 38 (2013) 594–601

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X-ray diffraction spectrum of
TiO2 nanoparticles
 The crystalline phases can be
confirmed by the presence of
(101), (004) and (200)
diffraction peaks, in the case of
anatase phase and
(110), (111) and (002) for the
rutile crystalline phase.
 Using the Scherrer equation, it
was observed that the mean
crystallite grain size of the
TiO2 particles was around 23
nm and 28 nm for anatase
and rutile phases, respectively.
Experimental Results: NNPs Characterization

28. Vasco Teixeira
Experimental results: Atomic Force Microscopy (AFM)
AFM
bitumen
Bee-likestructures
pH 810×10m 5×5m
pH 5.510×10m 5×5m
 The use of a solution with acidic pH is not feasible
for the production of asphalt binders
 Using a solution with a pH = 8 is possible to identify
the maintenance of bee-like structures, that are
characteristics of the bitumen. In fact, for this
pH, the average size of the observed structures is of
the same order of magnitude (610 nm) from those
that were identified in the original bitumen surface.

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100(%)
0
0







 

A
AA

The results reveal that the highest efficiency values
were achieved by using the spraying technique (60%
compared to 45% obtained by volume incorporation
technique).
Experimental results: Evaluation of the photocatalytic
activity of TiO2 modified asphalt mixtures
The produced samples
were immersed in a MB
aqueous solution and
absorbance was
measured for different
time intervals to evaluate
the photocatalytic
degradation.

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Experimental results: Surface Wettability
 The produced samples present a surface with a hydrophilic nature. It is
observed that there is a reduction of the contact angle (56%) in the
samples modified by using the spraying technique (which also showed
the higher photocatalytic efficiency).
t = 0 min
q = 57º
t = 30 min
q = 25º
Practical Point
of View
 A higher degree of hydrophilicity helps these surfaces being more
easily and effectively washed away by rainwater, thus minimizing
accidents.

31. Vasco Teixeira
Performance of photocatalytic activity of TiO2 modified
asphalt mixtures after laboratory-simulated wear tests
Some concerns were raised that the TiO2 nanoparticles would be
removed by action of vehicle tires and harsh service conditions
 Using a scaled wheel, passing
over the samples surface, a
laboratory-simulated wear test
was performed.
 The wheel has applied a load
of 500 N. After three hours, the
wear test was stopped and
then the samples were once
again subjected to a
photocatalytic test.
Experimental results: photocatalytic activity of
TiO2 modified asphalt mixtures after wear tests

32. Vasco Teixeira
Conclusions
 Nanotechnology can produce novel materials with unique and improved
properties/functions of high interest to construction industry as shown.
 Window IR modulation by doped-VO2 thermochromic films with different
at.% and different switching temperatures were successfully achieved and are
new potential candidates for improving the energy efficiency of buildings.
 The application of nanotechnology has the potential to improve solar cells
efficiency significantly and it will add value by reducing manufacturing costs in
PV industry and turn possible novel Building Integrated PV concepts.
 In this presentation we also focused in our recent project: the benefits of adding
titanium dioxide nanoparticles in asphalt mixtures to include functional
photocatalytic properties (self-cleaning and pollution reduction).
 Two application methods were used: a water-based titanium dioxide solution, applied
by spraying, and using TiO2 as an additive (volume incorporation) to the base asphalt
mixture. The spraying modification technique, unlike the volume incorporation, has great
advantage because it does not require any changes to a bituminous paving structure,
thereby reducing the modification costs.

33. Vasco Teixeira
THANK YOU FOR YOUR
ATTENTION
“This work was supported by FEDER through the COMPETE Program and by the Portuguese Foundation for Science and
Technology (FCT) in the framework of the Project PTDC/FIS/120412/2010”
- EU-7FP-200431-NMP-LARGE-1-2007-“INNOSHADE—Innovative Switchable Shading Appliances
based on Nanomaterials and Hybrid Electrochromic Device Configurations”
- EU-6FP-017761-CRAFT-2005-"TERMOGLAZE: Production of thermochromic glazings for energy
saving applications“