Interfacial chemical bonding and

What this expression says is that the measured strength of an adhesive bond, Fmeas) is first dependent upon the mechanics of the adhesive bond itself, M. Secondly, it is dependent upon the work of adhesion, Thirdly, it is dependent upon the physical properties of the adhesive such as the complex Young s and shear moduli, E and G, respectively, and the same moduli for the adherend. Fourthly, it is dependent upon the fracture resistance of the material, Fifthly, it is dependent upon the strength of interfacial chemical bonds, and sixthly on the amount of mutual... 

Because of the match in the atomic spacings between GaAs and AlAs, 99.999% of the interfacial chemical bonds are saturated. 

Fig. 3. The lattice-matched double heterostructure, where the waves shown in the conduction band and the valence band are wave functions, T(x), representing probability density distributions of carriers confined by the barriers. The chemical bonds, shown as short horizontal stripes at the AlAs—GaAs interfaces, match up almost perfecdy. The wave functions, sandwiched in by the 2.2 eV potential barrier of AlAs, never see the defective bonds of an external surface. When the GaAs layer is made so narrow that a single wave barely fits into the allotted space, the potential well is called a quantum well. Because of the match in the atomic spacings between GaAs and AlAs, 99.999% of the interfacial chemical bonds are saturated.

The work of adhesion is also related to the force needed to break chemical bonds at the interface on the atomic scale. When bonds form at the interface of two solids, restructuring can occur at both sides of the interface, thereby optimizing the strength of the interfacial chemical bond. This restructuring is related to the adsorbate-induced restructuring processes and to the phenomenon of epitaxy that was discussed in Chapters 2 and 5. It involves the movement of atoms perpendicular, as well as parallel, to the interface. We may call this movement the work of interface restructuring It involves surface atoms as well as atoms two to three layers away from... 

Formation of durable chemical bonds is an obvious means to stabilize the interface and has been demonstrated for phenolic/alumina joints [25] and for silane coupling agents [26,27]. However, for most structural joints using epoxy adhesives and metallic adherends, moisture-resistant chemical bonds are not formed and mechanical interlocking on a microscopic scale is needed between the adhesive/primer and adherend for good durability. In these cases, even if moisture disrupts interfacial chemical bonds, a crack cannot follow the convoluted interface between the polymer and oxide and the joint remains intact unless this interface or the polymer itself is destroyed. 

YANG Qi-xiang and ZHOU Qin-li, "The ESCA and AES Studies of the Interfacial Chemical Bonding between Aluminum and Chromium(III) Fumarato-Coordination Compound," in Ref. 14. 

There are some interdependent adhesion mechanisms which govern the particle/ matrix interfacial strength in particulate composites such as mechanical interlocking, molecular entanglement, secondary force interactions, electrostatic attraction, chemical bonding, and polymer diffusion. 

Matrix-rubber particle adhesion is an important parameter for rubber toughening. For effective rubber toughening, rubber particles must be well bonded to the thermoset matrix. The poor intrinsic adhesion across the particle-matrix interface causes premature debonding of particles, leading to catastrophic failure of the materials. Nearly all the studies [9, 193, 2-10] have been concerned with reactive rubbers as toughening agents, and showed that dispersed particles have interfacial chemical bonds as a consequence of chemical reactivity. 

---