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Smart Materials in Architecture
Santina Di Salvo1, a *
1 PhD Architect Researcher of Department of Architecture of Palermo, Italy
aemail: santina.disalvo@unipa.it
Keywords: smart materials, efficiency, architecture, nanotechnology, interactivity
Abstract. The project activity presides over the choice of materials and technical capacity within
two dimensions of action: the previous knowledge and the tension about the future. That allowed us
to identify the succession of the “technological and material” paradigms that have come and gone,
featuring the project with the arrival of new materials and production processes. The advent of
composite smart materials has challenged all the materials overturning the features.
Introduction
All materials are evolving with the development of technology. Intelligent materials, or smart
materials, are the ultimate expression of the “paradigm of engineered materials”, as a model of
technical and scientific capacity to intervene in the matter at molecular level (Fig. 1). The
technological and material paradigm is that of designed materials. The materials within these
categories are often called “advanced” if they combine the properties of high (axial, longitudinal)
strength values and high (axial, longitudinal) stiffness values, with low weight, corrosion resistance,
and in some cases special electrical properties. Generated by micro and nanotechnologies, these
materials are implementing the potential of artificial intelligence [1]. They interact and respond to
external stimulation by modifying their properties; to detect and communicate the environmental
parameters and the human body; to meet and interact on a predetermined basis with human beings
and the environment, developing the real physical behavior. For various aspects present similarities
with biological organisms and natural systems.
During the past decade, intelligent materials have received increasing attention from scientists
because of their technological potential. The class of smart materials with the greatest number of
potential applications to the field of architecture is the property-changing class. These materials
undergo a change in a property or properties - chemical, thermal, mechanical, magnetic, optical or
electrical - in response to a change in the conditions of the environment of the material. The
conditions of the environment may be ambient or may be produced via a direct energy input such as
a field of forces, with stimuli in their environment or the simple human presence; materials capable
of emitting light, budge and communicate interactively, allowing extraordinary performance [2].
International Journal of Engineering Research in Africa Submitted: 2016-03-14
ISSN: 1663-4144, Vol. 23, pp 72-79 Revised: 2016-03-21
doi:10.4028/www.scientific.net/JERA.23.72 Accepted: 2016-03-21
© 2016 Trans Tech Publications, Switzerland Online: 2016-04-05
All rights reserved. No part of contents of this paper may be reproduced or transmitted in any form or by any means without the written permission of Trans
Tech Publications, www.ttp.net. (#68715598-18/07/16,12:31:47)
Figure 1. Insulating transparent aerogel.
Figure 2. A 6 µm diameter carbon filament (running from bottom left to top right) siting atop the
much larger human hair.
Methodology
Sensitivity, interactivity and communication skills feature “thinking objects”, connecting
surfaces and interactive microenvironments, setting a world more concerned about our needs and
desires. In fact, materials, devices and intelligent systems are a universe that extends well beyond
our expectations on the matter, which may be able to self-repair and self-generate an increasingly
behavior more similar to that of living beings. The ability to edit and create new materials,
designing the specific functions they have to perform, is an important opportunity for the built
environment. Technically, the potential value is enormous, but it implies a radical transformation of
the design process and, with it, a new design philosophy. The design of the object of design moves
from the “artifact to performance”. Priority is given to the point of view of design, in which issues
relating to “are identified as” and “why” of the systems performance that integrate smart materials.
The examples provide a broad overview of smartness solutions in various application areas and in
some cases it is possible to note that the same benefits are achieved through the application of
different materials and technologies [3]. The correspondence between material, shape and function
in its consolidated significance now lost its importance, and create a new concept of form as
International Journal of Engineering Research in Africa Vol. 23 73
essence a concept that coincides with the behavior and the very meaning of the material. In addition
to assessing the benefits of new materials, the risks that they imply to understand how best to tackle
the deliberate abuse of the technologies are also considered. Taking possession of the new
instruments and the ability to go “back and forth” between the micro and the macro, between the
old and the new, technologists and designers will be able to make use of smart materials to create a
sense of well-being and comfort, expression of our needs and desires.
The materials are classified by functional typologies and defined for what they are “capable of
making”. This information encourages the creation of interactive and sensitive relational
configurations that, through “design of the performance”, are transformed into objects and services,
systems and structures, spaces and surfaces, according to new behavior patterns [4].
Experimental and results
Sustainability and nanotechnology - Nanotechnology develops methods of manipulation of
materials and systems at the atomic and molecular level. In the nineties the growing interest in
nanotechnology is born with the ability to control matter at the structural level for which each
molecule can be positioned in an orderly way. In smart materials the feature is implicit in the same
characteristics of the atomic or molecular structure, according to the principle that every induced
stimulus (input) follows an active response and reversibile which generates variable behaviors and
changeable performance (output) that are adapted to the environmental context. The composite
materials with nanoparticles, such as carbon nanotubes, nano rings, nanocrystals, nanowires of
silicon, considerably improve the macroscopic properties of traditional materials. The main feature
of smart materials thus consists in the ability to perceive external stimuli and react by adapting to
changes in environmental conditions in a reversible way. The objects, the surfaces, the
environments relate to the senses and with the human body, improving performance and the
subjective experience of use in the report and in the ratio of human-machine interaction. The project
becomes interactive, sensitive, communicative, conscious, adaptive, accountable, in one word
“smartness”.
An intelligence ambient can be a room (house, office, hospital, home for the elderly…) crammed
with sensors, actuators and computers that are interconnected and connected to the internet. The
separate parts are controlled and activated by an ‘intelligent agent’ software that is familiar with the
preferences of the occupants and able to adapt the environment according to their wishes. The
occupants may communicate with this ambient intelligence by means of speech, movements or
other actions. The new concept has, in essence, the objective of improve the quality of life of users
in daily activities and protect the environment to achieve sustainable development.
Advanced materials for architecture: coatings - We said that the smart materials are advanced
materials insofar as they possess intrinsic mechanical properties, thermal and chemical, and thermal
performance standards, acoustic and structural significantly higher than traditional materials. Often
they consist customized, designed and produced according to the different specificities, which can
be of climatic or structural nature. It is not uncommon to see a coating system designed to meet
certain requirements and a set of advanced materials used for that purpose. As for the materials,
technology innovation has found growth opportunities both through scientific research, or because
of the contamination between different fields of application of already known materials. An
example is the use of titanium in architecture, as a covering element, a new application field for this
material, previously used for its high cost only in areas where it is not possible to come to terms
with the economy, in particular in the shipbuilding, automotive and aerospace industries [5]. The
opportunity for innovation was presented at the design for the Guggenheim Museum in Bilbao (Fig.
2) where Frank Gehry has used titanium for the outer casing in a highly innovative way, either for
using a material until then never used to “coat the architecture” that to have exploited an IBM
software technology, 3D Catia program, which had only applied until then in the aerospace field
[6]. Therefore the outer casing, the “skin” of the building has become one of the first revelatory
elements of this material.
74 International Journal of Engineering Research in Africa Vol. 23
The attractive look, the possibility to get it in different finishes and colours its light weight its
mechanical characteristics and above all, its weather resistance, making it pretty eternal even in the
toughest environments even when it is used very thin they have projected its use in architecture.
The first applications of titanium in this area date back to the seventies. Japanese are the most
important achievements until the mid-nineties: among these are the covers of the Tokyo Electric
Power building, designed to stop the leakage of radiation from the reactors at the Fukushima
nuclear power plant damaged after the disaster of 2011; and covers of the Fukuoka Dome, the
largest baseball stadium in Japan (1994).
Today, titanium is used for exterior and interior cladding, for coverage of prestigious buildings,
for artworks such as sculptures and monuments, decorative details of buildings or urban furniture.
Generally it is possible the use of titanium in its natural silvery coloration which, moreover,
presents different aspects to, of the lamination type, blasting, pickling or passivation endured. In
particular, the processing of the material is critical because, depending on how it is carried out, can
lead to obtain matt surfaces, or, as opposed, to finishes able to give coloured reflections with tones
that change in relation to the variation of the light. Therefore, there are yellow or gray tones in the
morning if it is not sunny, to an intense, bright white around noon, pink at sunset , blue at night or
with iridescent and multicoloured flashes when illuminated with artificial light. This change is
clearly visible in the masterpiece of Gehry in Bilbao, which has been defined by Buckart as a sort of
giant metal band that forms a landscape that, for the multitude of angled and rounded planes, carries
the light, making it at every point of a different colour, up to form a large effect monochromatic
ranging from gold to blue and from pink to white [7].
Figure 3. Guggenheim Museum, Bilbao.
The interactive facade Windswept - Nowadays a coating is not enough to make a building look like
a more elegant building. There is the need that this skin make truly innovative and justified its
application. Another extremely attractive example of this new concept of skin / facade, it is given
by the so-called “Windswept facade”, ie an interactive facade designed to move around depending
on the air currents, revealing the exact wind direction and also putting on the scene the artistic
potential of natural ventilation. Designed by American designer Charles Sowers, the installation of
this facade is currently been integrated on the exterior of the Randall Museum in San Francisco
(Fig. 3, 4) and is a kinetic experiment that connects art and science. In fact, the installation
combines not only an original design, it is able to make visible something that usually is not visible
to the naked eye: create an architectural scale instrument for observing the complex interaction
between wind and the building. Wind gusts, rippling and swirling through the sculpture, visually
reveal the complex and ever-changing ways the wind interacts with the building and the
environment. To realize this wind-driven kinetic façade Sowers took over a year, during which he
worked to assemble 612 freely-rotating directional arrows in anodized aluminum on the exterior of
International Journal of Engineering Research in Africa Vol. 23 75
the Museum. Each of these arrows has been installed on a special rear bracket, so as to allow the
arrows to move in one direction at the first breath of wind. Windswept is 20′ high x 35′ long. It is
installed on an 40′s era board-formed concrete building. I attach an image of that wall before the
sculpture was installed. The whole piece sits off the wall to allow an equal volume of air to enter a
ventilation intake mounted in the middle of the existing wall.The wind arrows are made of brake-
formed anodized aluminum. The arrow axles are mounted to a standard metal architectural panel
wall system consisting of 25 panels. The panels had holes punched in a 12″ x 12″ grid pattern into
which the installation contractor secured rivet nuts to accept the stainless steel axles. Once the
panels were installed the arrow assemblies were threaded into the rivet nuts. The mechanism is able
to make the same facade as an artwork of looking changeable. Not surprisingly, the project was
commissioned to Sowers from the San Francisco Arts Commission, with the specific purpose to
create an interactive installation [8].
Figure 4. Charles Sowers’ installation at Randall Museum in San Francisco.
Figure 5. Charles Sowers’ installation at Randall Museum in San Francisco.
76 International Journal of Engineering Research in Africa Vol. 23
Classification of smart materials - Intelligent materials are classified on the base on the type of
stimulus (input) or the type of reversible reaction resulting (output). The materials are sensitive to
external stimulation induced by the electric force, magnetic, mechanical and thermal. Additionally,
smart materials react to small changes in environmental parameters such as temperature, pH,
moisture, brightness, noise and the presence of harmful substances. Generally, they are
distinguished according to the type of response that provide and which often coincides with the
function they perform. The reaction generates a behavior of adaptation to the stimulus that causes
the transformation of the intrinsic properties of the material, such as viscosity, dielectric constant,
electrical resistance, etc.. Depending on the type of reaction to external stimulation, smart materials
can be classified into seven functional groups: materials that change colour, shape, temperature,
convert light, emit light, carrying light and move.
The new glass for smart “window” - At Lawrence Berkeley National Laboratory in Berkeley,
California, a team of researchers led by Delia Milliron, has developed a new technology that allows
to obtain a particular type of glass that can work dynamically controlling the flow of heat and light
which passes through it, modulating it according to different weather conditions, through the
transparency. The new glass of this type of smart window exploits the interaction of two highly
conductive materials: the nanocrystals of indium oxide and tin, and a glassy matrix of niobium
oxide; the interaction between the two conductors allows a selective control of visible light and
heat, so as to obtain natural lighting inside without increase of heat, typical of the hottest months.
Compared to current technologies, in which the control of the radiation also leads to a darkening of
the glass surface, carrying some drawbacks about quality of the lighting of the environments, the
conformation in three layers of the smart window allows the user a personalized and optimal control
of heat, of light and transparency. In a perspective of energy saving this new approach would allow
a considerable saving of resources and optimal management of costs, especially for cooling and
lighting in residential buildings and in particular of the commercial ones, where the use of large
glass is widespread [9].
From the point of view of the study of materials what is most important is that they were able to
demonstrate that it is possible to combine very different materials to achieve new properties that can
not be achieved with single-phase materials. The interaction of the two materials makes it possible
to block approximately 50% of the heat and 70% of visible light compared to the use of the
individual materials. Since 2013, the researchers are working with a start-up based in Oakland,
California, to lower production costs, still too high. One possibility would be to use the crystals in
the zinc base in place of expensive indium oxide and tin, experimentation that is giving good
laboratory results (Fig. 5). A simple window can also perform functions of energy supply, as a solar
panel. This is shown by the research on “Large-area luminescent solar concentrators”, made by a
research team from the University Milano-Bicocca in collaboration with the Los Alamos National
Laboratory (U.S.A.). The team has developed solar concentrators: these are simple slabs of
plexiglass “doped” with special fluorescent nanoparticles that capture and concentrate
sunlighttransforming the windows of buildings in clean energy generators, without giving up the
transparency of the material.
New technological solutions to illuminate the monuments - The lighting of facades and monumental
buildings also requires special attention to uniform functional and aesthetic criteria, with the utmost
respect of their formal and environmental features. Technological solutions for lighting facades and
monuments are various: the lighting technology allows, in fact, effective solutions to illuminate
monumental facades, with projectors that create grazing illumination of the wall structure so as to
reduce light pollution. It is possible to use equipment collected to the ground or wall, from small
spotlights to LED source, the projector which uses several watts, to fluorescent lamps. It is
desirable, furthermore, to employ devices for the illumination that ensure a good control of the
luminous flux directed to the outside of the area to be illuminated, for example headlamps with
small lamps. In the lighting of the exterior is very widespread the use of small spotlights and
between these the tendency is to use punctiform sources such as LEDs or xenon lamps, both
International Journal of Engineering Research in Africa Vol. 23 77
characterized by a long duration in time. In particular, the solutions with the LEDs offer more and
more high levels of performance and an extreme precision in the addressing of the flow, as they
allow the possibility to edit the light intensity and chromatic effects, essential for dynamic lighting
for both interiors and exteriors.
The monument lighting systems usually consist of lighting fixtures with high output sources,
with particular regard to the resolution of issues associated with light pollution. To prevent light
from coming out from the façade to be illuminated displays or asymmetric reflector headlamps can
be installed. It is good to choose products that enhance, through the light they emit, the architectural
space in which they are installed. For this reason, often it is favored a warm light rather than
fluorescent lamps. To help reduce environmental pollution and promote energy savings, they are
starting to be used also working devices with photovoltaic modules that fit harmoniously in historic
buildings, monuments and buildings of historical interest [10]. Photovoltaic technology offers
evident economic and environmental benefits, however until now the aesthetic and visual impact of
the modules were the obstacles to its spread, also with the high costs of sale and installation and it is
likely that in the future greater care in design and a wide range of photovoltaic products will allow
further expansion of the the entire PV industry making it competitive [11] (Fig. 6).
Conclusions
Experience has shown that technological innovation occurs when a change process reaches a
critical mass sufficient to overcome the inertia of the “classic” system, and only by supproting
innovative processes it is possibile to implement much more ambitious plans compared to current
practices. Therefore, it requires dialogue and confrontation with even distant skills that can be
inspiring but at the same time require awareness of their specific knowledge and the goals that we
intend to pursue. Through the results obtained by recent experimental projects, also implemented,
there have been substantial changes in the way of seeing and living the built environment: the user
becomes from spectator to protagonist. The projects considered here show the interest and ideas that
are droning on research regarding innovative and reliable systems technology, to ensure the
enhancement and enjoyment of the built landscape and a smart use of buildable space.
In this historical moment characterized by the use of high technology, the continual
technological research may represent an opportunity for further renewed debate on innovation and
sustainability concepts. We refer to technologies that can be used successfully in order to preserve
the built environment, setting the stage for an “intelligent building”, thinking consciously about the
same time formal and construction problems, the functional and technical issues and system
implications, favoring a consideration on the multiple dimensions that underlie the conscious use of
new materials.
Figure 6. Smart window.
78 International Journal of Engineering Research in Africa Vol. 23
Figure 7. PV panels.
Sources of photos
Fig.1 - source from a document online: repubblica.it/scienza_e_tecnologia/aerogel.
Fig.2 - document online: niilmuniversity.in/coursepack/humanities/Industrial_Development.pdf
Fig.3 - by the Author
Fig.4 - photo by Archdaily
Fig.5 - photo by Archdaily
Fig.6 - document online: rinnovabili.it/innovazione/finestra-intelligente.
Fig.7 - by the Author
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10.4028/www.scientific.net/JERA.23
Smart Materials in Architecture
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