Adhesion studies

ToF-SIMS has been applied to a range of polymer problems such as adhesion studies of elastomers based on brominated poly(isobutylene-co-4-methylstyrene) and diene elastomers [8], polyvinyl chloride [9], epoxy resin aluminium [10, 11], glass rubber [12], squalane brass [13], and sealants [14], 

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Perhaps the most significant complication in the interpretation of nanoscale adhesion and mechanical properties measurements is the fact that the contact sizes are below the optical limit ( 1 t,im). Macroscopic adhesion studies and mechanical property measurements often rely on optical observations of the contact, and many of the contact mechanics models are formulated around direct measurement of the contact area or radius as a function of experimentally controlled parameters, such as load or displacement. In studies of colloids, scanning electron microscopy (SEM) has been used to view particle/surface contact sizes from the side to measure contact radius [3]. However, such a configuration is not easily employed in AFM and nanoindentation studies, and undesirable surface interactions from charging or contamination may arise. For adhesion studies (e.g. Johnson-Kendall-Roberts (JKR) [4] and probe-tack tests [5,6]), the probe/sample contact area is monitored as a function of load or displacement. This allows evaluation of load/area or even stress/strain response [7] as well as comparison to and development of contact mechanics theories. Area measurements are also important in traditional indentation experiments, where hardness is determined by measuring the residual contact area of the deformation optically [8J. For micro- and nanoscale studies, the dimensions of both the contact and residual deformation (if any) are below the optical limit. 

Numerous AFM imaging techniques have been developed and commercialized to monitor topography, friction, mechanical response, capacitance, magnetic properties, etc. However, adhesion measurements require the tip to come into, and out of, contact to measure attractive and adhesion forces. Therefore, other than to select an analysis region, most imaging techniques are not useful for adhesion studies. Instead, measurements are necessarily based on force-displacement curve approaches. 

Hayes, R.A. and Ralston, J., Application of atomic force microscopy in fundamental adhesion studies. In Mittal, K.L. and Pizzi, A. (Eds.), Adhesion Promotion Techniques — Technological Applications. Dekker, New York, 1999, pp. 121-138. 

Knowledge gained from cell adhesion studies with SAMs has been used to develop culture substrates with the appropriate cell adhesion glycoproteins for different types of cells [7-10], Stem cells, capable of self-renewal and differentiation into multiple cell types, are found in embryonic and adult tissues. Pluripotent stem cells, like embryonic stem cells and induced pluripotent stem cells, have been developed in vitro. These cells are expected to provide cell sources for regenerative medicine. Various culture conditions have been developed to enable expansion of these cells without loss of their multi- and pluripotency and to induce differentiation into viable cells with specific functions. 

Faucheux N, Schweiss R, Liitzow K, Werner C, Groth T (2004) Self-assembled monolayers with different terminating groups as model substrates for cell adhesion studies. Biomaterials... 

Table 6. Adhesion studies of poly(ether imide) on polyimide ...

Bray, R. C., Quate, C. F., Calhoun, J and Koch, R. (1980). Film adhesion studies with the acoustic microscope. Thin Solid Films 74,295-302. [219]... 

It should be noted that approximately 1% of the APS used in the last experiment appears to be APS monomers before dilution. Could this low monomer concentration be responsible for adhesion It should be noted that the residual monomers present in this highly-oligomerized solution correspond to a 0.001 vol % solution if one were to remove the oligomerized APS. As a result of this observation, the dependence of the adhesion of thin films to native-oxide silicon wafers as a function of the concentration of the APS under conditions of T H stress was investigated. Adhesion studies were performed using APS solutions with concentrations that varied from the industry standard of 0.1 vol % down to 0.00001 vol %. The test wafers were prepared and exposed to T(200) and T(500) conditions as discussed above. Adhesion was measured by 90° peel test, as discussed above. The results of this study are presented in Fig. 13. The Lx-axis is APS concentration which decreases from left to right. The y-axis is the adhesion in the units of g mm"The three curves are the results at T(0), T(200) andT(500). 

Johnson et al. reported adhesion studies of some polymeric matrix membrane by using PVC, Urushi and copolymer (vinylchloride/vinyl alcohol copolymer matrix membrane with treatment of tetrachlorosilane) by using an ultrasonic bath (10). They also reported the use of Urushi gives improved adhesion lasting over 5 hours and that in some cases the membrane lasted for over 20 hours. The stability of the Urushi matrix ISFETs was discussed in detail elsewhere (6). 

Yoon TH, McGrath JE (1991) Adhesion study of peek/graphite composites. Int SAMPE Symp Exhib 36(1) 428... 

Adhesion studies of epoxy resins modified with high modulus and high glass transition temperature thermoplastics have shown adhesion can reach or even exceed that of the unmodified resin. The use of flexible polyamides or flexible epoxides resulted in shear strength increases in epoxy systems employed by Cunliffe et al. [144],polyethersulfones [18,145],polyetherimides [109,146,147], and polyetherketones [148-150]. 

Gopal Ganesan, P. and Eizenberg, M. (2003), Chemical vapor deposited RuOx films Interfacial adhesion study. Mater. Sci. Eng. B Solid-State Mater. Adv. Technol., 103(3) 213-218. 

Lu Z, Ryde NP, Babu SV, Matijevic E. Particle adhesion studies relevant to chemical mechanical polishing. Langmuir 2005 21 9866-9872. 

Lanckmans F, Brongersma SH, Varga I, Poortsmans S, Bender H, Conard T, Maex K. A quantitative adhesion study between contacting materials in Cu damascene structures. Appl Surf Sci 2002 201 20-34. 

Lawson et al. (2000) examined the migration of constituents from solvent-free adhesives used to bond 12 pm PET film to 45 pm LDPE. The technique of MALDl-MS, a soft ionisation technique capable of looking at sample mixtures over a mass range of 150-500,000 Da without prior separation, was employed. The adhesives studied were based on a solution of mixed isomers of MDl in polymeric MDI with either polyether or polyester-based polyols. Pouch testing of cured laminates with distilled water was undertaken (two hours at 70 °C) with the LDPE surface in contact with the water. 

From the XPS analysis results, it was found that TMS plasma coatings prepared in a closed system have a carbon-rich surface, which is similar to TMS polymers followed by methane plasma deposition, i.e., T/C as described in a flow system. The adhesion study also showed that the T/C plasma treatment on aluminum alloy provided excellent adhesion to spray paint primers. The primer adhesion performance of closed system TMS plasma polymers was also examined. Since the porous surface... 

The thermoplastic resins that were used for the adhesion studies are considered to be tough, not easily crystallizable polymers. They are as follows, with designated labels assigned to each structure ... 

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