Fibers are all around us. Different types of fibers exist, but in most cases we do not notice them because they are used in a product. In case an object is much longer as it is wide we consider it a fiber. Fibers have specific properties for the product in which they are used. This blog will describe the different ways how these fibers can be classified and how their performance can best be analysed. Hint: it has something to do with putting fibers under a specific type of microscope. You're about to discover the most suitable microscopy technique for fiber analysis, so do read on!
If you search online the word fiber you will see that fibers are classified as natural fibers and engineered fibers. We will focus on the engineered fabrics and especially the non-wovens.
Are engineered fabrics
Have a targeted structure and targeted properties
Are manufactured by high speed and low-cost processes
Are based on the technologies of the creation of textiles, papers, and plastics.
Diapers, napkins, air filters, hydraulic filters, construction products etc. are some examples of products containing non-wovens. The fibers in these products are called nanofibers as they can have a diameter < 1µm. Why are they so small? Because you can create higher efficiency products for better air filtration, water absorption, lifetime improvement, etc.
Key in this process is to understand the properties of non-wovens to be able to optimize the output. Changing the structure of non-wovens requires equipment to examine or test the material’s properties. This can be:
Chemical analysis - emission-, absorption spectrometry, XRF, XPS
Mechanical testing – tensile, abrasion, puncture
Microscopy – optical, electron optical (SEM), AFM.
Electron microscopy techniques for fiber analysis
Microscopy techniques are imperative to evaluating the performance of a filter, for instance. There are different ways to get a microscope view of fibers. Optical inspection has been the industry standard for the last decades. However, it has become insufficient for many new applications because fiber dimensions are below the resolution limit of an optical microscope.
Atomic force microscopy is a technique that can be used in the micron range, but it is a very slow process and can cause physical probe issues.
So what's the best microscopic view of fibers one can obtain? We suggest you look into scanning electron microscopy (SEM):
The best microscopy technique for fiber analysis: scanning electron microscopy (SEM)
With a higher depth of field and greater image contrast, use of a scanning electron microscope (SEM) is becoming the new standard for characterizing filtration materials. An SEM image affords a quick and high-resolution visualization of filter media. Elemental analysis, via energy dispersive X-ray spectroscopy (EDS) with SEM, allows for the identification of elements in the fibers or particulates.
Karl Kersten is head of the Application team at Phenom-World, world’s leading supplier of desktop scanning electron microscopes. He is passionate about the Phenom product and likes converting customer requirements into product or feature specifications so customers can achieve their goals.