Nanoparticles

Here are detailed notes based on the two pages titled "Nanoparticles" and "Uses of Nanoparticles":

📘 Nanoparticles

🔹 Definition & Size Categories

Particles are classified by their diameter:

Particle Type

Diameter Range

Also Known As

Coarse particles (PM₁₀)

2500 nm to 10,000 nm (2.5 × 10⁻⁶ m to 1 × 10⁻⁵ m)

Dust

Fine particles (PM₂.₅)

100 nm to 2500 nm (1 × 10⁻⁷ m to 2.5 × 10⁻⁶ m)

Nanoparticles

1 nm to 100 nm (1 × 10⁻⁹ m to 1 × 10⁻⁷ m)

Contain a few hundred atoms

  • Nanoscience studies particles in the nanoscale (1–100 nm).

🔸 Nanoparticles Have a Large Surface Area to Volume Ratio

Why It Matters:

  • Surface area to volume ratio affects particle behavior.

Key Concepts:

  1. Formula:

    Surface area to volume ratio=surface areavolume\text{Surface area to volume ratio} = \frac{\text{surface area}}{\text{volume}}

  2. As particle size decreases, the surface area to volume ratio increases.

  3. Example Comparison (from the page):

    • 100 nm cube:

      • Surface area: 60,000 nm²

      • Volume: 1,000,000 nm³

      • Ratio: 0.06 nm⁻¹

    • 10 nm cube:

      • Surface area: 600 nm²

      • Volume: 1,000 nm³

      • Ratio: 0.6 nm⁻¹

  4. Smaller particles = larger surface area compared to volume.

  5. Implications:

    • Materials behave differently at the nanoscale.

    • Often less material is needed for the same effect (e.g., in catalysts).

📘 Uses of Nanoparticles

🔹 Nanoparticles Can Be Used in Lots of Things

  1. Catalysts:

    • High surface area to volume ratio helps reactions.

  2. Nanomedicine:

    • Nanoparticles can be absorbed more easily by the body.

    • Can deliver drugs to targeted cells.

  3. Electronics:

    • Conduct electricity → used in electric circuits.

  4. Antibacterial Properties:

    • Used in surgical masks, wound dressings, and deodorants.

  5. Cosmetics:

    • Improve moisturisers without making them oily.

🔸 Health Effects of Nanoparticles Are Not Fully Understood

  1. Nanoparticles are useful, but effects on the body are still being researched.

  2. Some concerns:

    • Products may be released before safety is fully tested.

    • Long-term health impacts are not well known.

  3. Consumer Protection:

    • Products should be clearly labelled.

    • Consumers should have the choice to use them or not.

  4. Example: Sunscreen

    • Better UV protection than traditional creams.

    • Unclear if nanoparticles enter the body or damage cells.

    • May harm the environment when washed away.