Лако-красочные материалы — производство

It is evident from this brief overview of adhesion technology, nature, and science that many different specialists have an interest in the definition of what adhesion is, in the observing and measurement of the adhesive forces, in the chemical modification of surfaces to control adhesiveness, in improving adhesion so that aircraft do not fall apart, and in reducing adhesion so that cars do not seize up. In other words, adhesion is an interdisciplinary subject. Indeed, it connects many different subjects because of its common function and value.

We set out to address these issues, attempting to build a bridge of adhesion between the different disciplines. In the next chapter, the old debates about the phenomena and theories of adhesion are rehearsed. This allows us to focus on acceptable definitions of molecular adhesion. Then the logical theory of adhesion is expounded by defining the ideas, the terms, and symbols more carefully in order to work out the connections between them in Chapter 3. Thus, the laws of adhesion begin to be recognizable in a general form.

Two new sciences are developing now to enlarge our ideas about the laws of adhesion: Atomic Force Microscopy (AFM), which for the first time has allowed us to measure molecular forces; and computer modeling (CM), which has pushed the theory of molecular adhesion onto a new level. These new arguments are described in Chapters 3 and 5 to give an overview of the three laws of adhesion.

Having defined our framework of adhesion theory and measurement, it is then possible to cover the different application areas of adhesion science in Chapters 9-16. Starting with the adhesion of particles, which is fundamental to a molecular argument, we move on to colloids, pastes, and cells. Then the industrial areas are covered in electronics, films, adhesive joints, and composite materials (see Fig. 1.17). Finally, there is a discussion of the future of adhesion and how the description of adhesion phenomena may develop in the years to come.

There is a problem that in some areas, such as fracture of joints, the mathematical analysis has become so detailed that it is incomprehensible to the

chemist. Yet this mathematics often does not take into account the fact that molecules exist, whereas the chemist starts his theoretical argument from the molecular premise. This gulf of assumptions has to be crossed.

Chemists are fascinated by adhesion because they know that different molecules will provide different levels of tackiness; physicists are challenged by the fact that adhesion is very difficult to measure; material scientists see that all substances contain a multiplicity of interfaces which dominate the properties; geologists recognize that the soils and sands of the Earth’s crust are controlled by adhesion; biologists see adhesion as the connection between cells and living structures. And engineers of all kinds, from dentists, to cement constructors, through aircraft designers, computer scientists, chemical engineers, powder technologists, and pharmacists, see adhesion as a common thread in their subjects.

Unfortunately, there is a lack of common language and methodology across the boundaries of these disciplines. Would an aircraft designer understand what the parasitologist is talking about in a discussion of adhesion molecules like integrin? At present, the word “adhesion” itself means different things in separate subject areas. Some authors have gone so far as to say that molecular adhesion does not exist, and that the phenomena of sticky objects can be described by other mechanisms.19

This book is needed to rationalize the science and technology of molecular adhesion across the whole range of specialisms. It is important that we all agree what the word “adhesion” means, with a definition acceptable to both dentists and rocket engineers. A blood cell adheres one million times less than a sticky label, and that label sticks one million times less than an aircraft wing. The several scales at which adhesion operates are illustrated in Fig. 1.17 which shows molecules adhering to a cell surface, cells adhering to paint, paint on a wing and the wing on an aircraft. We have to solve the problems of measuring over such widely ranging scales and of finding suitable units and standards.