Question

Nanomaterials have particle size in the range

• A. >100 \(\mu\)m
• B. 1-100 nm
• C. 1-100 \(\mu\)m
• D. <1 nm

Hint:

At least one dimension must be in the 1-100 nm range:
- Thin films are nanostructured in 1 dimension.
- Nanotubes and nanowires are nanostructured in 2 dimensions.
- Nanoparticles are nanostructured in all 3 dimensions.

Answer 1

The Correct Option is B

Step 1: Understanding the Question:
The question asks for the standard dimensional size range that defines a material as a nanomaterial.

Step 2: Detailed Explanation:

• Defining Nanomaterials: In materials science and nanotechnology, a nanomaterial is formally defined as any natural, incidental, or manufactured material containing particles where at least one external dimension falls within the nanoscale.
- The nanoscale is universally defined as the range from

1 to 100 nanometers (nm).
- One nanometer is equal to one-billionth of a meter (\( 10^{-9} \text{ m} \)).

• Unique Properties of Nanoscale Materials: When particle dimensions are reduced to the 1-100 nm range, materials begin to exhibit unique physical, chemical, optical, and mechanical properties.
These novel properties arise due to two main phenomena:
1.

Quantum Confinement Effects: At very small scales, the electronic and optical properties of materials deviate significantly from those of bulk materials.
2.

High Surface-to-Volume Ratio: As particle size decreases, the fraction of atoms located at the surface increases dramatically, making nanomaterials highly reactive and excellent catalysts.

• Analysis of Incorrect Options:
- Sizes in the micrometer range (Options A and C, \( \mu\text{m} = 10^{-6} \text{ m} \)) represent bulk or micro-grained materials.
- Dimensions below \( 1 \text{ nm} \) (Option D) approach the atomic scale and represent individual atoms or simple molecules, rather than particulate nanomaterials.


Step 3: Final Answer:
Therefore, nanomaterials have a particle size in the range of 1-100 nm, matching Option (B).