APPLICATIONS OF SMART MATERIALS IN NANOTECHNOLOGY Shashwat Vimalkumar Joshi
email: svjoshi93@gmail.com
Metallurgy Department Government Engineering College, Sector-28, Gandhinagar-382028, Gujarat, India.
ABSTRACT New materials named ‘Smart materials’ are developed which have one or more properties that can be significantly altered in a controlled manner by exterior stimuli, such as stress, temperature, moisture, pH, electric or magnetic fields. Smart materials mostly consist of shape memory alloys and polymers, automatic actuators, piezoelectric materials, pH-sensitive polymers, chromogenic systems, self-healing systems. The property that can be altered influences what types of applications the smart material can be used for. The best way to understand the smart material concept is to look at its uses. Smart materials may work completely on their own or as part of a larger smart system. For example, doctors may use shape memory alloy staples used to set broken bones. In this case, the material works as both a sensor and an actuator as the patient’s body heat activate the staple to close and thereby clamp the break together. In the last decade, a wide range of novel smart materials have been produced for aerospace, materials science, sensing and actuation, optics, electromagnetic structures, control and engineering, information processing and so forth. Furthermore there is increased activity in integrating smart materials with nanotechnology and nanoscience to develop novel materials for the applications in nanomaterials, nanomedicine, nanoelectronics and molecular nanotechnology (Molecular assembler, nonorobotics, mechanosynthesis, nanofoundry and nanoreactor). Nanofoundry is a foundry that performs at scale similar to nanotechnology. The closest thing that nature has to a nanofoundry is the simplest biological cell. Nanotechnology would permit control of matter at the level of atoms and molecules which would form the building blocks of smart materials. In more the field of Smart Materials and Nanotechnology is very diverse with application ranging from bioengineering to photonics.
INTRODUCTION TO SMART MATERIALS
INTRODUCTION TO NANOTECHNOLOGY
Smart materials are those whose properties can be changed or altered significantly by applying some external stimuli like stress, temperature, moisture, magnetic/electric field, change in pH etc. Smart materials are highly responsive and have a great capacity to sense and response to any environmental change. Hence they are also known as ‘Responsive materials’ [1]. No moving parts, high reliability, low power requirement and provide new capabilities that are presently not possible are main advantages of smart materials. Common smart materials are [2]: Shape Memory Alloys Piezoelectric Materials Magnetostrictive Materials Active Fluids Optical Fibre Bragg Grating Sensors Temperature Responsive Polymers Photomechanical Materials Self-healing Materials
The first well documented talk on the possibilities of Nanotechnology entitled as “There is Plenty of Room at the Bottom” was made by one of the most distinguished American physicists, Richard Feynman (1918-1988) on December 12, 1959, before the American Physical Society meeting held at Caltech. The term “Nanotechnology” was first proposed by K. Eric Drexler in the 1970’s [3]. Nanotechnology is science and technology done at the nth degree of minuteness i.e., at the scale of atoms and molecules. It is the use of materials and devices so small that nothing can be built any smaller. Range of the size of nonmaterials is 0.1nm to 100nm. A nanometre is 1 billionth of a metre i.e., 10-9nm. A nanometre is to us what a glass marble is to the earth. Some Subfields and related fields of Nanotechnology are Nanomedicine, Nanobiotechnology, Nanolithography, Nanoelectronics, Nanomagnetics, Nanorobotics, Molecular nanotechnology[4].
ADVANCED SMART MATERIALS Quantum Tunnelling Composite (QTC) is an example of modern smart materials [5]. A QTC is a perfect insulator in its normal state but when it is compressed, it becomes a perfect conductor. It can be used as pressure sensors. Its conductivity is directly proportional to the applied pressure. In normal physics, an electron cannot pass through an insulation barrier. Where as in quantum physics, a wave of electron can pass through an insulator. According to this theory, QTC is working.
QTC
Before pressure application Light pressure application
Full pressure application
APPLICATIONS OF SMART MATERIAL IN NANOTECHNOLOGY Many applications like medicine, cryonics, environment, aerospace, tissue engineering, catalysis, information and communication, construction etc in which nanotechnology is used or can be used. For example nanosensors, nanoconductors, nanoinsulators are used in making of space suits in aerospace applications [6]. Modern smart materials like QTCs, thermocolour sheet, phosphorescent sheet, magnetic sheet, Rigid PVC Foam plastic, Ventricular sheet, Anodized effect card, Galvanized effect card etc. can be used in nanotechnology at molecular level. One of the modern smart materials, QTC can be used as pressure sensors at nanoscale in making of space suits for the comfort of Astronauts. REFERENCES: [1] www.azonano.com/article.aspx?ArticleID=1877. [2] en.wikipedia.org/wiki/Smart material. [3] www.newworldencyclopedia.org/entry/Nanotechnology. [4] Vimal S. Joshi, Nanotechnology: An analysis, Raj Publishing House, Jaipur [2010]. [5] www.peratech.com/qtcmaterial.php. [6] en.wikipedia.org/wiki/List of nanotechnology applications. ACKNOWLEDGEMENT: The author is sincerely thankful to Prin. J. V. Dave, Dr. G. H. Upadhyay, Prof. Anup Chandra and Miss. Priyanka Ghai for their discussion and guidance.