Surfaces and adhesion properties

Bendinger, B., Rijnaarts, H. H. M., Altendorf, K. and Zehnder, A. J. B. (1993). Physicochemical cell-surface and adhesive properties of coryneform bacteria related to the presence and chain-length of mycolic acids, Appl. Environ. Microbiol., 59, 3973-3977. 

Surface tension is an important determinant of the surface and adhesion properties of polymers. In both solids and liquids, the forces associated with molecules inside the material are balanced because each molecule is surrounded on all sides by like molecules. On the other hand, molecules at the surface are not completely surrounded by the same type of molecules, generating unbalanced forces. There-... 

Polyolefins belong to the most widely used class of polymers in many applications, such as in packaging, building, or transport industries. A combination of polyolefins with other materials can lead to an improvement of various properties. Many polyolefins belong among nonpolar polymers with low polarity and surface energy these polymers excel rather poor adhesion properties with various materials [1], and therefore, these polyolefins require the improvement of their surface and adhesive properties for many applications. In practice, the modification procedure selection for the improvement of the adhesion properties of diflerent polyolefins depends mostly on the required demands for the adhesive joints [2]. 

The surface and adhesive properties of iPP modified by UV radiation in the presence of POCI3 have been studied. Modification of iPP by UV/PCXZI3 results in an increase in surface energy of polymer as well as in an improvement of the mechanical work of adhesion of modified iPP to more polar polymers. 

On the other hand, perfluorinated polymers likepoly(tetrafluoroethylene), (PTFE), as one of the most important examples, represent a polymer class which is in particular characterized by its special surface and adhesion properties. Perfluorinated segments in polymers often result in strongly nonpolar surfaces with reduced wettability of water or organic molecules, reduced adhesion and yielding, excellent gliding, and antisticking properties, and, in particular, chemical inertness [13,14]. 

Further, the techniques of Scanning Electron Microscopy (SEM), Specular Reflectance Infrared Spectroscopy (SRIS), and Electron Spectroscopy for Chemical Analysis (ESCA) have proved complementary in this investigation of the relationships between adherend surfaces and adhesive properties. As SRIS results have shown the presence of adhesive on all fracture samples, ESCA and SEM results further clarified the nature of the fracture surface through the presence or absence of a Ti ESCA spectrum and the observation or lack of observation of the substrate structure in the SEM photomicrographs. It is concluded from the results of the three techniques that for the Set I samples, cohesive failure was noted for 219D2 whereas adhesive failure was noted for 220D3. Cohesive failure was noted for samples lm2-517 and lmp2-516 and adhesive failure was noted for 2m2-515 in Set II. 

J. Schultz, L. Lavielle and H. Simon, Surface and Adhesion Properties of Carbon Fibres, Proc. Int. Symp. on the Science and New Applications of Carbon Fibers 84, Toyohashi University of Technology, Japan. 1984. p. 125. 

Solders should flow promptly and smoothly over the surfaces of the parts to be joined. This property depends on the surface tension, viscosity, and adhesive properties of the molten solder. Finally, the color of a solder should match that of the metal employed, and its physical properties should be at least as good as those of the metal, in order for the joint not to be a source of weakness (150). 

Treatment of polymer surfaces to improve their wetting, water repulsion, and adhesive properties is now a standard procedure. The treatment is designed to change the chemistry of the outermost groups in the polymer chain without affecting bulk polymer properties. Any study of the effects of treatment therefore requires a technique that is specific mostly to the outer atomic layers this is why SSIMS is extensively used in this area. 

The van der Waals and other non-covalent interactions are universally present in any adhesive bond, and the contribution of these forces is quantified in terms of two material properties, namely, the surface and interfacial energies. The surface and interfacial energies are macroscopic intrinsic material properties. The surface energy of a material, y, is the energy required to create a unit area of the surface of a material in a thermodynamically reversible manner. As per the definition of Dupre [14], the surface and interfacial properties determine the intrinsic or thermodynamic work of adhesion, W, of an interface. For two identical surfaces in contact ... 

In the development of the discussed fluorinated products a lot of fundamental insight has been gained into permeation and adhesion properties of surface-fluorinated polymers. Although this insight is not discussed in this paper, it may be of interest to mention a few significant fundamental discoveries and also to suggest directions for future development. 

Performance Cohesive and adhesive properties, surface free energy, and water uptake behavior affect disintegration and dissolution behavior... 

Many studies through the years have shown that selected properties of both the wood and the adhesive do affect adhesion. Although many wood and adhesive properties have been studied (see, for example, 53, 54, 55), wood extractives and thermal inactivation of the wood surface have received considerable attention recently and will be discussed in detail. 

Related to clearance time is the manner in which the nanoparticles attach to cells. Nanoparticles can be internalized or remain adhered to the surface. The mechanism is determined by the surface charge, adhesion properties, and chemical functionality of the cells with respect to the nanoparticle. 

The general properties of cured and uncured epoxy resins are reviewed in Chap. 3. The chemical structures of the resin and curing agent will determine these physical properties. They will also determine, to a great extent, the surface chemistry and adhesion properties of the final product. 

One of the major problems associated with bonding plated parts is the different surface conditions that can be caused by variations in plating equipment, process methods, and solution concentrations. These variables result in plated surfaces with broad conditions of surface finish and inconsistent metallurgical and adhesion properties. 

If in the case of aluminized silicone we were able to evidence a drastic difference between sputtering and evaporation, it happens not to be the case for aluminized PET (13). Our preliminary results on this latter polymer indeed show no marked differences between the two deposition processes, both giving strong chemical interaction. By contrast we have also observed that with noble metals such as Au, no chemical interaction is taking place with silicone substrate with both deposition processes. This tells us that the nature of the polymer substrate and of the metal are most important for the interfacial and adhesive properties. The fundamental parameter seems to be the reactivity of both constituents of the interface. It has been confirmed by Pireaux et al. that the carboxylic function is one of the most reactive surface entity (14) and indeed for PET, the adsorption site for the Al atoms is found to be the carboxylic function (13). During this interaction, Al is oxidized and the diffusion of O into the Al film can occur. 

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