Surface characterization methods

The final technique addressed in this chapter is the measurement of the surface work function, the energy required to remove an electron from a solid. This is one of the oldest surface characterization methods, and certainly the oldest carried out in vacuo since it was first measured by Millikan using the photoelectric effect [4]. The observation of this effect led to the proposal of the Einstein equation ... 

Surface Characterization Methods Principles, Techniques, and Applications, edited by Andrew J. Milling... 

Due to diffraction effects of micron-sized mirrors in a regular array, commonly used techniques for surface characterization based on interferometry are inefficient. To overcome the diffraction effects we have developed a novel surface characterization method with an incoherent light source, based on the Foucault s knife-edge test (Zamkotsian and Dohlen, 1999). Since Leon Foucault introduced the knife-edge test in the last century (Foucault, 1859), it has been widely used for testing optical surfaces (see Ch. 3). The test offers a simple way of obtaining easily understandable, qualitative information of the surface shape. 

Results obtained by CPAA for composition and partial mass thickness have been shown to be consistent with the results obtained via other analytical methods. The main advantage of the use of CPAA as a surface characterization method are its purely instrumental character, requiring no sample preparation, its high accuracy, and its low detection limits. 

Comparison of Scanning Tunneling Microscopy with Other Surface Characterization Methods... 

Wedd M.W., Particle sizing in the sub-micron range by laser diffraction, in Particle and Surface Characterization Methods, Muller R.H. and Mehnert W., eds.. Scientific Publishers, Stuttgart, 1997, 57. 

A Au-coated substrate is another model surface, to which many surface characterization methods can be applied. To achieve surface-initiated ATRP on Au-coated substrates, some haloester compounds with thiol or disulflde group were developed [80-84]. Self-assembled monolayers (SAM) of these compounds were successfully prepared on a Au-coated substrate and used for ATRP graft polymerization. Because of the limited thermal stability of the S - Au bond, the ATRP was carried out at a relatively low temperature, mostly at room temperature, by using a highly active catalyst system and water as a (co)solvent (water-accelerated ATRP). 

Th,s book compiles and describes much of the recent growth in developments and techniques in the fields of surface science and surface analysis. In the past decade, techniques, once mainly of interest to academia, have been adapted to solve a variety of industrial research and development problems. Advanced surface-characterization methods have moved quickly out of the research laboratory and into commercial instrument manufacture. Indeed, this growth has generated a highly specialized, even bewildering, array of techniques—an alphabet soup of techniques in fact. 

Recent developments in surface-characterization methods have been made possible to a great extent by technological advances in areas such as lasers, ultra-high vacuum, charged-particle optics, and computer science. The surface-analysis techniques are commonly used to probe the interface between two phases after one phase is removed, but there is now a growing demand for additional methods for in situ interface characterization. 

Theoretical models based on first principles, such as Langmuir s adsorption model, help us understand what is happening at the catalyst surface. However, there is (still) no substitute for empirical evidence, and most of the papers published on heterogeneous catalysis include a characterization of surfaces and surface-bound species. Chemists are faced with a plethora of characterization methods, from micrometer-scale particle size measurement, all the way to angstrom-scale atomic force microscopy [77]. Some methods require UHV conditions and room temperature, while others work at 200 bar and 750 °C. Some methods use real industrial catalysts, while others require very clean single-crystal model catalysts. In this book, I will focus on four main areas classic surface characterization methods, temperature-programmed techniques, spectroscopy and microscopy, and analysis of macroscopic properties. For more details on the specific methods see the references in each section, as well as the books by Niemantsverdriet [78] and Thomas [79]. 

Thus the combination of surface characterization methods with polymer characterization methods gives new insights into the properties of this important industrial copolymer system and demonstrates the effectiveness of these methods in distinguishing between different techniques of polymerization. 

Besides images of the surface, AFM provides additional information that makes it unique as a surface characterization method for the etched, chemically modified capillaries. These measurement features include root means square (RMS) roughness,... 

Behaviour of the photoresist in long-time measurements in water. The photolithographic development is a very short process. It usually takes not more than a few minutes. Thus effects as swelling and slow dissolution play a minor role. In contrary, most of the physico-chemical surface characterization methods used in this study extend over more than ten minutes if equilibrium is to be waited for, over hours. Therefore, changes of the properties of photoresist layers during immersion in water is of great interest. 

It should also be noted that nitrogen is not an unbiased probe adsorbate. Obviously the surface accessibility for irregular materials depends on the size of the probe molecule a large probe cannot foUow the irregularity of the surface. Analyte molecules are usually larger than nitrogen molecules, and may not be able to penetrate aU pores. Thus only a fraction of the surface area is involved in analyte retention. To fulfill lUPAC recommendations for surface characterization methods [9], the most suitable method depends on the specific application. Recently an approach that involves IPR ion adsorption proved effective. The best probe to determine the packing area... 

For the sake of completeness it is noted that many of the surface characterization methods treated in sec. 1.2 also apply for assessing porosity. This applies in the first place for atomic force microscopy (AFM), by which. In... 

Since it utilizes a force instead of a current, the technique is capable of imaging both conducting and nonconducting materials. AFM can make three-dimensional quantitative measurements with a higher resolution and on a wider variety of materials than any other surface characterization methods. 

A.W. Adamson, A.P. Cast, Physiccd Chemistry of Surfaces, e.g. 6th ed., Wiley (1997) sec. VII.5, reviews some of these methods. See also chapter 8 of the book by Rusanov and Prokhorov, mentioned in sec. 1.17c, and the more recent review H.-J. Butt, R. Raiteri, Measurement of the surface tension and surface stress of solids, in Surface Characterization Methods Principles, Techniques and Applications, A.J. Milling, Ed., Marcel Dekker (1999) ch. 1. 

D.Y. Kwok, A.W. Neumann, Contact Angle Measurements, in Surface Characterization Methods. Principles, Techniques and Applications. Surfactant Series no. 87, A.J. Milting, Ekl., Marcel Dekker (1999) chapter 2, p. 37-86. (Review, many practical hints, 191 refs.)... 

Summary Silicone copolymers are hybrid matmals with varying phase separation levels. The polymers themselves as well as surfaces formed by these copolymers were analyzed by a variety of polymer and surface characterization methods. Atomic force microscopy was found to be especially suitable for analysis of thin polymer films. Both surface and bulk properties are dominated by the domain size and the silicone content. 

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