Basics of Nanochemistry

Unit - II

Chapter 2

Nanochemistry

INTRODUCTION

The prefix (nano), in the word nanochemistry, means a billionth (1 × 10^-9m). Atoms are very small and the diameter of a single atom can vary from 0.1 to 0.5 nm. It deals with various structures of matter having dimensions of the order of a billionth of meter.

BASICS OF NANOCHEMISTRY

1. Nanoparticles

Nanoparticles are the particles, the size of which ranges from 1-50 nm. Generally they are obtained as colloids. The colloidal particles have a tendency to remain single crystal and hence are called as nanocrystals. A large percentage of atoms in nanocrystals are present on the surface.

Nanocrystals possess electronic, magnetic and optical properties. Since the nanoparticles exhibit an electronic behavior, governed by the quantum physics, they are also called as quantum dots.

2. Nanomaterials

Nanomaterials are the materials having components with size less than 100 nm at least in one dimension.

• Nanomaterials, in one dimension, are layers such as a thin films or surface coatings.

• Nanomaterials, in two dimension, are tubes such as nanotubes and nanowires.

• Nanomaterials, in three dimension, are particles like precipitates, colloids and quantum dots.

3. Nanochemistry (or) Nanoscience

(Nanoscience is defined as the study of phenomena and manipulation of materials at atomic, molecular and macromolecular scales.

4. Nanotechnology

Nanotechnology is defined as the design, characterization, production and applications of structures, systems and devices by controlling size and shape at 10-'m scale or the single-atomic level.