Adhesion states

Bulletin SC-54-57, Shell Chemical Company also in Bolger, J., Structural Adhesives State of the Art, Chapter 7 in Adhesives in Manufacturing, G. L. Schneberger, ed., Marcel Dekker, New York, 1983, p. 155. 

Using the hard sphere adhesive state equation proposed by Baxter (16), it is possible to calculate the demixing line due to interactions. This state equation corresponds to the exact solution of the Percus-Yevick equation in the case of an hard sphere potential with an infinitively thin attractive square well. In our calculation we assum that the range of the potential is short in comparison to the size of the particles (in fact less than 10 %). 

Drain, K. F. Gatechalr, L. R. Short Course on Fundamentals of Adhesion, State University of New York, 1988. 

The first law of adhesion states that all atoms adhere. Therefore we would expect that blocks of material placed in good contact should stick together. This idea had been studied by Tyndall in 1875 and investigated further by Budgett in 1911. The objective was to show that adhesion between flat plates could be larger than that expected from atmospheric pressure. 

The importance of these interface structuring phenomena stems from the large number of possible adhesion states that could exist as different molecules are arranged at the surfaces. Little is known about the possible triggering or... 

One of the best understood examples is that of mica surfaces, pressed into contact through water, as described in Section 6.6. The plot of force versus separation is not smooth in this case, but shows sharp oscillations as layers of water molecules are squeezed out of the gap between the surfaces. When plotted as an energy diagram, this shows that the surfaces can exist in several metastable adhesive states, depending on how many water layas have been removed, as shown in Fig. 8.7. 

In this case, the particles can exist in three possible states gas-tike particles undergoing Brownian motion at long range, soft adhesion in the secondary minimum and hard adhesion in the primary minimum. There is also the energy barrier between these adhesive states, slowing the approach to the primary minimum. 

Ref P. M. Hergenrotherr "High-temperature Adhesives," lecture notes for the course on "Fundamentals of Adhesion," State University at New Paltz, New York, Nov. 1983.)... 

Adhesion state in which two surfaces are held together by interfacial bonds. 

ASTM test method covers determination of the blocking point of adhesive layers. Also, non-adhesive states that can be activated by heat or solvent are included. 

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