Different types of smart materials.

1. Smart Materials
Presented by
Shubham Kumar Gupta
Roll no. 13/ME/143
Department of
Mechanical Engineering

2. In this presentation….
 Introduction of smart material
 Some examples of smart materials

3. What are smart materials?
• Smart materials are materials that
have one or more properties that can
be significantly altered in a controlled
fashion by external stimuli, such as
stress, temperature, moisture, pH,
electric or magnetic fields.

4. What are the examples?
• Piezoelectric materials
• Shape memory alloys
• Magnetic shape memory alloys
• PH sensitive polymers
• Halochromic materials
• Chromogenic systems

5. Classification of SMART materials
Type of SMART
Material
Input Output
Piezoelectric Deformation Potential Difference
Electrostrictive Potential Difference Deformation
Magnetostrictive Magnetic Field Deformation
Thermoelectric Temperature Potential Difference
Shape Memory Alloys Temperature Deformation
Photochromic Radiation Color Change
Thermochromics Temperature Color Change

6. What are Piezoelectric
materials?
• Piezoelectric materials are materials that
produce a voltage when stress is applied.
Since this effect also applies in the reverse
manner, a voltage across the sample will
produce stress within the sample. Suitably
designed structures made from these
materials can therefore be made that bend,
expand or contract when a voltage is
applied.
• Buzzers are piezoelectric.

8. What are shape memory
alloys?
• Shape memory alloys and shape
memory polymers are
thermoresponsive materials where
deformation can be induced and
recovered through temperature
changes.

9. What are shape memory
alloys?
• An example is NiTinolTM
(Nickel Titanium)
• Above its transformation temperature,
Nitinol is superelastic, able to withstand a
large amount of deformation when a load is
applied and return to its original shape when
the load is removed. Below its
transformation temperature, it displays the
shape memory effect. When it is deformed it
will remain in that shape until heated above
its transformation temperature, at which
time it will return to its original shape.

11. Magnetic SMA
• Magnetic Shape Memory alloys are materials that
change their shape in response to a significant
change in the magnetic field.

12. PH sensitive polymers
• pH-sensitive polymers are materials which
swell/collapse when the pH of the surrounding
media changes.
• There are two kinds of pH sensitive materials: one
which have acidic group (-COOH, -SO3H) and swell in
basic pH, and others which have basic groups (-NH2)
and swell in acidic pH. Polyacrylic acid is an
example of the former and Chitosan is an example
of the latter. The mechanism of response is same
for both, only the stimulus varies.

13. Halochromic Materials
• Halochromic materials are commonly materials that
change their colour as a result of changing acidity.
One suggested application is for paints that can
change colour to indicate corrosion in the metal
underneath them.

14. Chromogenic systems

15. Thermochromic
Materials which changes color with changes in
temperature.
General materials used are:
V2O5 ,
Cholesteryl nonanoate,
1,2,3-triazole,
Octadecylphosphonic acid.
General applications:
 Inks;
Dyes;
Papers;
Plastics.

16. Photochromic
• Photochromism is the reversible transformation of colour upon
exposure to light. This phenomenon is illustrated in sun glasses.

17. Electrochromic Materials
These materials change their optical behavior with
application of electrical voltage.
Their behavior is basically characterized by the amount of
light they allow to pass through them.
Transparent and looks
like ordinary glass
Application of small
voltage turns it opaque
(bluish and dark)

18. THANK YOU