The following article will give a brief overview of what nanoparticles are and their different uses. The article will begin by explaining the criteria needed for nanoparticles and how to use the standard form. The article will then go on to explain the different properties of nanoparticles and the different uses they can have.
- This article is about nanoparticles.
- We will see what nanoparticles are, the order of magnitude and its standard form.
- We will analyse what are the properties of nanoparticles and how we calculate the surface area to volume.
- We will finish by seeing what are the uses of nanoparticles.
What are Nanoparticles?
Nanoparticles are particles whose diameters are between 1 to 100 nm. Nanoscience is the study of structures that are between 1nm and 100nm.
It is important to note that 1nm is 1·10-9 m.
To understand how small nanoparticles are, below is a table illustrating the sizes of other “small” particles.
Particle | Diameter (nm) |
Atoms and Small Molecules | 0.1 |
Nanoparticles | 1 to 100 |
Fine Particles (PM2.5) | 100 to 2,500 |
Coarse Particles (PM10) | 2,500 to 10,000 |
It is also important to remember that coarse particles are sometimes referred to as dust and fine particles can be referred to as particulate matter.
Orders of Magnitude
To understand the scale at which nanoparticles exist, we often have to compare their size with other particles. Often, one of the easiest ways to describe how much bigger or smaller an object is in comparison to another, we use orders of magnitude.
If a nanoparticle has a diameter of 67.7 nm and the diameter of an atom is 0.68 nm, how many times larger is the nanoparticle than the atom?
We begin by rounding each number to the same amount of significant figures. This is going to result in an approximation, rather than a precise answer due to the rounding. In our example, this gives us:
68 nm and 0.68 nm
Next, to find the order of magnitude, we divide the numbers:
68 nm/0.68 nm = 100
From this, we can conclude that the nanoparticle is about 100 times bigger than the atom.
Often when making approximations we use the following symbol, instead of the equals sign![]()
Standard Form
Standard form is used a lot throughout this topic. It is a good way of writing down a very large or small number. Within this part of the article, we will have a quick overview of the standard form and how to use it.
Numbers represented using standard form come in the format:
A · 10n
“A” is the base number and is between 1 to 10.
“n” is the power of 10 we multiply “A” by to get to the original number.
If we wish to represent the number 0.000078 using standard form, it would be 7.8 · 10-5.
7.8 is the base number and is between 1 and 10. To get from 7.8 to 0.000078, we multiply 7.8 by 10-5. This gives us our “n” value.
What are the Properties of Nanoparticles?
Nanoparticles often have many different properties compared to the same material which is in bulk. This is because of the high surface area to volume ratio that nanoparticles have.
Surface area to volume ratio increases, the smaller the object is. For example, if the side of a cube was to decrease by a factor of 10, the surface area to volume ratio would also decrease by a factor of 10.
This sometimes means that smaller objects can be more effective than normal-sized objects. This is because often we use smaller quantities of the smaller object than we would normally use.
Due to nanoparticles having very large surface area to volume ratios, it makes them applicable in a lot of uses.
How do we Calculate the Surface Area to Volume?
To calculate the surface area to volume ratio, we need to first find the surface area of the object and the volume of the object. To then find the ratio, we divide these two quantities by each other.
If we have a nanoparticle in the shape of a cube that has sides of 17nm, what would the surface area to volume ratio be?
We begin with this question by calculating the surface area and the volume of the nanoparticle. The surface area of the object would be:
17nm · 17nm = 289 nm2 (Area of one square face)
6 · 289 nm2 = 1734 nm2 (Area of all six square faces)
Total surface area = 1734 nm2
The volume of the object would be : 17nm · 17nm · 17nm = 4913 nm3
We then divide the surface area of the object by the volume to find the ratio: 1734 4913 = 0.35 (to 2sf) It is important to remember that there are no units for the surface area to volume ratio.
What are the Uses of Nanoparticles?
Nanoparticles are used in lots of different applications. A few of these include:
Nanoparticles are favoured in these applications due to their small sizes and high surface area to volume ratio.
Nanoparticles - Key takeaways
- A nanoparticle has a diameter between 1 to 100nm.
- 1nm is 1 · 10-9m.
- Nanoparticles have a high surface area to volume ratios which make them ideal in a lot of applications.
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