NANOscientific

ISO FOR SURFACE CHEMICAL ANALYSIS USING SCANNING PROBE MICROSCOPY

The Nakajima Laboratory's expertise is polymer nanomechanics, in other words, investigating nano-scale structures and properties of polymeric materials, by which it connects knowledge in nano to macroscopic world. "No swallow written in textbooks" is our motto. The lab is currently involved in several national projects such as CAO SIP, CAO ImPACT, JST CREST.

At Tokyo Institute of Technology, Dr. Ken Nakajima is working with other institutions to create a new ISO Standard for using SPM for surface chemical analysis. This ISO is important to the rubber tire industry, where Dr. Nakajima works closely with all the leading manufacturers. He has pioneered methods  for Nanorheological Mapping of Rubbers by AFM and AFM-based Nanomechanics rubber-filled interfaces. “We need to know the distribution and intervention of nanometer particles,” comments Dr. Nakajima. “These properties can only be measured using AFM.”

The importance of mechanical property mapping is evident by the top five tire manufacturers who work with Dr. Nakajima’s group at the Dept. of Chemical Science and Engineering at the University of Tokyo.

The new ISO Standardization will have a significant impact on the rubber tire and other industries as they look at the value-added proposition and standards for integrating nanoparticles into their products. The tire industry specifically is very interested in the interfacial region because engineers know that the interface of the nanoparticles and rubber is important.

An example for the tire industry is to add carbon nanoparticles for durability and then measure the nanometer particles distribution and intervention. “Industry executives need qualitative measurements,” adds Dr. Najajima. His group consults and corroborates with industry and many of his students find industry jobs when they leave academics.

Dr. Nakajima works with many AFM manufacturers and sees a solution offered by every manufacturer based on that company’s product and strengths. When specifically asked about Park Systems AFM, he replied, “Park Systems big advantage is in measurement accuracy because their AFM’s biggest feature is having an accurate piezoelectric XY scanner, Park’s XY scanner is wonderful and they are also strong in the semiconductor industry.”

Summary of the ISO currently underway

ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO technical committees. Each member body interested in a subject for which a technical committee has been established has the right to be represented on that committee. International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.

Surface chemical analysis

Scanning probe microscopy — Procedure for the determination of elastic moduli for compliant materials using atomic force microscope and the two-point JKR method.

Scope: This international standard describes a procedure for the determination of elastic modulus for compliant materials using atomic force microscope (AFM). Force-distance curves on the surface of compliant materials are measured and the analysis uses a two-point method based on Johnson- Kendall Roberts (JKR) theory[1,2]. This International Standard is applicable to the compliant materials of elastic moduli ranging from 100 kPa to 1 GPa. The spatial resolution is dependent on the contact radius between an AFM probe and the surface and is typically 10 nm.

Atomic force microscope (AFM) is a family of scanning probe microscope (SPM) used to image surfaces by mechanically scanning a probe over the surface. In AFM, a surface force is monitored as the deflection of a compliant cantilever, which has a probe at its free end in order to interact with surfaces. AFM can provide amongst other data: topographic, mechanical and chemical information about a surface depending on the mode of operation and the property of the probe tip. Accurate force measurements and sample deformation measurements are needed for a wide variety of applications, especially to determine the elastic moduli of compliant materials such as organics and polymers at surfaces. For quantitative force measurements, the adequate selection of contact mechanics used in calculating the elastic modulus and the appropriate calculation procedure are required. This International Standard describes a procedure for the determination of elastic moduli for compliant materials using AFM. Force-distance curves measured on the surfaces of compliant materials are used for the calculation based on Johnson-Kendall-Roberts (JKR) two-point method.