What is AFM-IR?

AFM-IR, or atomic force microscopy based infrared spectroscopy is a form of chemical imaging which creates a visual image of components which make up chemicals, which uses extremely high powered microscopes. This is typically done with a radiation source to illuminate the sample which is being observed, as well as the usage of an AFM probe which detects thermal expansions from the radiation source. Also used is a high-powered imaging system to translate the probe’s movements into an image, and finally a detector array to categorise. AFM-IR places results in a three-dimensional block, which spans x and y dimensions.

AFM-IR has enormous application in a whole variety of fields. Whether it is chemistry, biology, medicine, pharmaceutical agricultural or industrial use, the ability to analyse substances and work our properties is vital. AFM-IR has quickly become one of the most powerful and efficient ways to characterise material surfaces, especially at nanoscale resolution. Nanoscale resolution is characterisation at a nanoscale level (as the name might imply!) with one nanometer (1nm) being equal to a billionth of a meter. Nanoscale technology is most useful for applications such as water purification, agriculture, computer manufacturing, and medicine.

AFM-IR typically works by using a pulsed infrared beam of radiation which is pointed at the material in question. An IR-transparent prism is placed between the material and the infrared beam in order to concentrate the infrared. As this Infrared beam touches the material in question, it will react on a molecular level. Typically, atoms within this material will start to vibrate due to the radiation, and will heat up. This will result in the molecules expanding. A cantilever is then used to oscillate on the material, and the oscillation is recorded onto a graph. This is then analysed, and a series of techniques can be then utilised to establish amplitudes and frequencies – or very simply, how much of a reaction the material displays to the radiation, and from that, all manner of things can be discovered.

AFM-IR is considered the most efficient and most accurate way of determining nanoscale structure, as well as chemical, mechanical and thermal properties in a material, and is an important part of R&D and quality assurance efforts in a wide variety of industries and professions.