Colloidal nanoparticles unlocked

Explore the world of colloidal nanoparticles, their applications, and analysis techniques

Why can’t we write the entire 24 volumes of the Encyclopedia Britannica on the head of a pin?

Richard Feynman asked this question in 1959. Although this feat seems physically impossible, his point was that there is nothing in the laws of nature that limits our ability to work at incredibly small scales. At the time, it was a lack of appropriate equipment and techniques that set the limits instead.

Fast-forward to the present day. Light scattering, nano tracking analysis, X-ray diffraction, X-ray fluorescence, laser diffraction: in research and industry alike, these techniques have unlocked the world of nanoparticles, materials with overall dimensions at the nanoscale (under 100 nm).

Many nanomaterials exist in the form of nanoparticles in dispersions. In other words, they are mixed with another material. This substrate stabilizes the nanoparticles – picture drops of water forming an adhesive net that keeps nanoscopic particles in place. The results of this process are called colloidal nanoparticles, and they have wide-ranging applications.

From electronics and energy conversion to medicine and detergents, this new world is filled with promise. Top-of-the-line analysis instrumentation is key in fulfilling that promise and safeguarding against potential risks. In this 6-blog series, we’ll share the applications and analysis methods associated with colloidal nanoparticles, as well as the techniques and instruments that are key to realizing their potential.

How to build your own colloidal nanoparticles

But how are these colloidal materials synthesized in the first place? There are three main approaches:

• Top-down approach: Breaking down bulk materials into smaller particles, which can then disperse in a liquid to form colloidal suspensions.
• Bottom-up approach: Building up nanomaterials from smaller building blocks, such as atoms, molecules, or ions.
• Colloidal stability: The stability achieved by nanomaterials when in colloidal form is due to surface interactions. If you add specific molecules to the particle surface, these interactions prevent aggregation and continue to ensure colloidal stability.

There’s nothing ‘nano’ about the benefits of nanomaterials

At the nanoscale, the physical and chemical properties of matter can be completely different. For example, graphene is a nanoparticle synthesized from graphite. The thermal conductivity range of graphite at room temperature is 800-2,000 W/mk, making it one of the most thermally conductive materials available. The range for graphene is over double that (3,000 – 5,000 W/mK). Non-magnetic elements can become magnetic; some nanomaterials even possess antiviral, antibacterial, and antifungal properties.

This has revolutionary potential. For example, tomorrow’s nano-computers could feasibly carry a nanoscopic capsule containing healing microbes and inject them directly onto disease-causing bacteria and viruses in an organism. Microscopic robots could repair or even assemble complex devices, or remove harmful substances from the environment.

The colloidal nanoparticle detective’s toolkit

Before mass-producing colloidal nanomaterials, however, we need to identify any risks they might pose to humans or the environment. Developing the right tools for material analysis is therefore key not only to unlocking the world of nanomaterials – but also to ensuring they’re safe to use.

To provide this level of precise and detailed analysis, Malvern Panalytical offers a range of technologies to determine the properties of colloidal nanoparticles. In the next five blogs, we’ll introduce these techniques, detail the risks they are designed to combat, and share the benefits they bring. Here’s a sneak peek at what we’ll explore…

• Light scattering: Measuring the intensity fluctuations of scattered light resulting from the movement of nanoparticles in suspension
• Nanoparticle tracking analysis (NTA): Defining the characteristics of individual nanoparticles by tracking their Brownian motion
• X-ray diffraction (XRD): Measuring the intensities and angles of X-rays that are scattered when they encounter nanoparticles
• X-ray fluorescence (XRF): Measuring the elemental identity and abundance of nanoparticle-forming atoms by the fluorescence ‘fingerprints’ when irradiated with X-rays
• Laser diffraction: Measuring size distributions through the angular variation in intensity of light scattered by a laser beam directed at nanoparticles

These are the instruments that ensure that every single word, letter, and piece of punctuation of the Encyclopedia Britannica can be added to the head of that pin. No need for a wheelbarrow to carry that copy around.

Stay tuned for our next blog on light scattering – and in the meantime, check out our dedicated nanomaterials page!