Nanoparticles have unique optical, magnetic, and mechanical properties compared to larger particles. Optically, their surface plasmon resonance leads to absorption and reflection of visible light that depends on particle size, causing various colors. Magnetically, they can be superparamagnetic and useful in applications like MRI contrast agents. Mechanically, carbon nanotubes have tensile strengths and moduli that are over 1000 times greater than steel.

1. PROPERTIES OF NANOPARTICLES

2. OPTICAL PROPERTIES
• Surface Plasmon Resonance (SPR)
• Plasmon-oscillations of the electron cloud
• Nanoparticles-high SA-more potential for SPR-
Visible region
• Very Small nanoparticles- absorption (SPR) blue-
green-reflection red-deep red colour
• Small nanoparticles- absorption (SPR) red-
reflection blue-pale blue colour
• Partcle size-bulk limit- absorption (SPR) IR-
reflection visible-clear/translucent colour

3. MAGNETIC PROPERTIES
• Super paramagnetism
• Great relevance to modern technology MRI
contrast agents, ferrofluid technology etc.
• Super paramagnetism-in small ferro and
ferrimagnetic substances
• Neel relaxation time –time between two flip
(magnetisation)
• Magnetisation appears to be in average zero-
superparamagnetic state

4. MECHANICAL PROPERTIES
• TENSILE STRENGTH-CNT ( 11000-63000 )MPa
• TENSILE MODULUS/YOUNGS MODULUS-
STIFFNESS- NT(1-5) TPa