Adhesion surface irradiation

Kessler and coworkers immobilized RGD peptides to a PMMA surface via a spacer incorporating an azobenzene unit [ 187]. The molecules were arranged in such a way that the RGD motifs were accessible to cells approaching the surface when the azo unit was in the E-form, and were hidden from the cells when the azo unit was in the Z-form. This enabled the reversible modulation of mouse osteoblast adhesion by irradiation with visible or UV light. However, the difference between on and off states is not very pronounced. Possibly, the accessibility of the RGD motif is not... 

Other topics recently studied by XPS include the effects of thermal treatment on the morphology and adhesion of the interface between Au and the polymer trimethylcy-clohexane-polycarbonate [2.72] the composition of the surfaces and interfaces of plasma-modified Cu-PTFE and Au-PTFE, and the surface structure and the improvement of adhesion [2.73] the influence of excimer laser irradiation of the polymer on the adhesion of metallic overlayers [2.74] and the behavior of the Co-rich binder phase of WC-Co hard metal and diamond deposition on it [2.75]. 

When the photostabilization of a polymer material is to be obtained through such a surface treatment process, it is all important to make sure that the protective effect will last throughout the service life and therefore to ensure a long-term adhesion of the coating onto the substrate. This can be best achieved by promoting a grafting reaction between the two elements (20). For that purpose, the photoinitiator was partly incorporated in the top layer of the PVC plate by a surface treatment with an acetone solution. Upon UV-irradiation of the resin-coated sample, the following reactions are expected to occur ... 

Considering that severe health hazards and diseases that can be induced by the adhesion and proliferation of bacteria on the surface of numerous materials, bioactive materials incorporated in the surfaces will be required. The cellulose-functionalised with porphyrin 69-71 and 80 were shown to kill gram positive and gram negative bacteria upon irradiation with visible light. Such materials could be used in industrial, household and medical environments, and more generaly in areas that would benefit from permanent and efficient surface disinfection.62 64... 

Modified PTFE surfaces show a high degree of biocompatibility with good cell adhesion and proliferation [7-11], However, the UV-treatment results also in a loss of mechanical stability due to the scission of polymer chains, especially for light-sources with wavelengths below 193 nm [6], Similarly to the ion implantation or plasma modification, also the UV light-irradiation is performed on both sides of a polymer foils in order to avoid the material torsion. 

One problem for the coated system is that the film is peeled off after prolonged irradiation. In order to have a more adhesive film, the surface of n-Si was modified with N-(3-trimethoxysilyIpropyl)pyrrole (22). Pyrrole was then electrodeposited on this modified electrode as shown in Eq. (24) 85). The durability of the coated poly(pyrrole) was improved by such a treatment of n-Si surface. The n-Si electrode coated only with poly(pyrrole) gave a declined photocurrent from 6.5 to 1.8 mA cm-2 in less than 18 h, while the poly(pyrrole) coated n-Si treated at first with 22 as Eq. (24) gave a stable photocurrent of 7.6 mA cm-2 for 25 h. When an n-Si electrode was coated with Pt layer before the deposition of poly(pyrrole), the stability of the semiconductor was improved remarkably (ca. 19 days)85b). A power conversion efficiency of 5.5% was obtained with iodide/iodine redox electrolytes. 

The irradiated components can be placed adjacent to sulfur-containing unvulcanized elastomeric compounds and, when necessary, coated with suitable adhesive between the contacting surfaces to ensure good bond after final cure of the tire. ... 

In XPS, on the other hand, photoelectrons, which are emitted when the sample surface is irradiated with a beam of x-rays, are analyzed. The emitted photoelectrons have discrete binding energies that are dependent on both the identity of the parent element and its chemical environment in the surface. Therefore, both the concentration and the chemical state of an element in the surface can be determined. Two advantages of XPS are that the incident x-ray beam is practically harmless to the surface and it also does not induce charging effects, so that the surface chemistry of adhesives and other insulators can readily be investigated 171 ... 

This micro device consists of a round or square micro chamber machined in a bottom plate sealed by a cover slip with double-sided adhesive tape [23], Sound irradiation was achieved by a PZT disk below. The PZT disk was bonded by super glue to the surface of the micro chamber. The PZT disk was driven by an HP functional generator... 

Several techniques including corona discharge [1], plasma treatment [1,3,4], flame treatment [1], and irradiation with UV light in the presence of a UV sensitive gas [5-8] have been developed to modify the polymer surface. The principle of those surface treatment technologies is to introduce polar groups onto the polymer surface. This provides significant improvement of wettability, paintability, biocompatibility and also adhesion to other polymers or metals. 

Modified Surfaces. It is frequently desirable to change the surface of a polymer. Nonpolar surfaces of plastics are characterized by static electricity buildup, non-wetting, poor adhesion, low printability, and poor dyeing. These disadvantages can be overcome by grafting polar vinyl monomers upon the surface by irradiation. A. S. Hoffman describes radiation grafting of polyelectrolytes upon nonpolar surfaces, and A. Chapiro and co-workers discuss radiation grafting of acrylic acid and vinyl pyridene upon Teflon films. 

---