Japanese company Teijin Ltd. delivers cutting-edge solutions across four business areas, including two primary ventures in materials and healthcare, alongside operations in IT and fibers and related products. Teijin’s philosophy is “enhancing the quality of life.”
Image Credit: Asylum Research - An Oxford Instruments Company
To remain at the forefront of materials development, Teijin has acquired Oxford Instruments’ Jupiter XR Atomic Force Microscope (AFM) at its Iwakuni Development Center. In a recent interview, Dr. Bunsow Nagasaka and Mr. Hirofumi Kurimoto at the Teijin Material Analysis Research Center discussed the Jupiter XR and their reasons for selecting the Oxford Instruments solution over 19 other AFM companies.
Teijin utilizes the Jupiter XR to evaluate and analyze a large range of samples to develop materials in pharmaceuticals, polymers, medical materials, and inorganics (carbon fibers to be specific).
Over two decades ago, Teijin’s Tokyo Research Center in Hino City acquired the company’s first AFM company. Early on, AFM was a novelty, offering brown-colored surface profile images and phase images through its measurement.
However, there were limitations to this technology: samples had to be very flat, the AFM was prone to vibration, and measurements were quite time-consuming. Attempts at measuring actual samples proved an almost impossible task. On top of that, at the time, the electron microscope was the ideal method for acquiring surface morphology images.
As it was possible to interpret the crystalline and amorphous portions of polymer materials by shape and the contrast of back-scattered and transmitted electron images, Teijin realized that running the AFM would not be as useful as originally hoped.
However, the need to evaluate the surface irregularities of individual fibers persisted. Measuring the roughness of a curved surface is exceptionally difficult, even when using a confocal laser microscope, so AFM would have been the best option for characterizing the fiber structure.
Moving ahead twenty years, the imperative to acquire more detailed structural insights into fibers has grown exponentially. As Teijin began to investigate how to upgrade its old AFM, it discovered that the Z range of the AFM (that is, the operating range in the height direction), is much bigger in modern AFMs compared to the past. This revelation suggested that it might be possible to measure and evaluate the surface of the fibers.
For demonstration purposes, cross-sectional samples were prepared by cryogenic ion milling from a polymer alloy cut and delivered to several AFM manufacturers. This was a cross-section of a polymer alloy with phase separation of the polyamide and epoxy phases. The critical focus was to determine whether the instrument could accurately characterize the structure (shape image) and elastic modulus, which shows the hardness distribution.
The first demo report from another AFM manufacturer revealed that there was noise in the surface profile, and, in the elastic modulus image, the hard and soft parts of the sample were reversed. This gave Teijin the impression that AFMs had not changed as much as expected.
The AFM company also noted that the roughness of the sample surface was far too large, implying that the sample itself was inadequate. This was discouraging as it showed this type of measurement would be difficult with AFM.
In contrast, the elastic modulus map and data acquired with the Jupiter AFM showed that the hard and soft polymer regions were correctly displayed, and the modulus values were accurate. Before these results, it seemed AFM would not be useful in this context. However, the Oxford data was on an entirely different level; perhaps AFM technology has evolved after all.
It is impressive that Oxford could acquire high-quality data, considering the challenging sample conditions—a limited amount of time given to prepare the cross-sections, and thus the final touches were missed. The noise in the measurements was at a different level and Oxford’s blueDrive photothermal cantilever excitation technology proved quite useful.
For Teijin, a key consideration in the evaluation of AFM technology was the ability to repeat the measurements independently. Mr. Kurimoto, who is relatively new to AFM, was able to perform the measurements and obtain accurate results. Compared to conventional AFM, the Jupiter XR can acquire images in a limited time with good repeatability.
For example, when measuring the surface of fibers in conventional AFM, the shape is barely discernible. In contrast, the Jupiter XR enables the observation of detailed surface morphology. Jupiter allows for easy cantilever tuning so the AFM can complete an analysis in half the required time or approximately two times the speed. The Jupiter XR is a high-performance instrument that is in full operation daily.
The Oxford AFM application team is outstanding. As Teijin does not have experts with experience using AFM from graduate school, the opportunity to receive technical support directly from the maker’s staff was a key consideration in the selection process. For instance, probe selection is vital for AFM measurements, but with numerous options available, it can feel overwhelming to decide which to choose.
Oxford’s expert team provides useful and accurate advice on selecting the optimal probes for each application. Oxford’s application staff are a reason enough to purchase this instrument. The employees at Teijin are extremely satisfied with the high performance of the Jupiter AFM, along with the exceptional technical knowledge of Oxford’s team.
This information has been sourced, reviewed, and adapted from materials provided by Asylum Research - An Oxford Instruments Company.
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