Modification depth measurement with

We are interested in measuring the modification depth for the samples treated with 1 M KOH aqueous solution at 22 °C for 10 min since surface topography and film thickness remain unchanged under these reaction conditions. The modified layer is thicker than the XPS sampling depth (approximately 100 A) since the XPS spectrum only displays the peaks due to the product. The RBS spectrum does not give a peak corresponding to potassium, so the modified layer is probably thinner than the limit of RBS sensitivity (approximately 300 A). These results indicate that the modification depth is in the range of 100-300 A which is an inaccessible zone for thickness measurement with usual techniques. 

Polyimide surface modification with KOH or NaOH aqueous solution is well defined. The reaction initially gives potassium or sodium polyamate which is then protonated with acid to yield polyamic acid. The outermost layer (5 A) of PMDA-ODA can be completely modified within a minute of reaction in KOH solution. The depth of modification can be measured by a method using an absorbance-thickness relationship established with ellipsometry and external reflectance IR. The modification depth of PMDA-ODA treated with 1 M KOH aqueous solution at 22 °C for 10 min is approximately 230 A. Surface topography and film thickness can be maintained while a strong... 

A modification of the above underwater method studied by Cook (p 37) is the measurement of the spall-dome velocity at the surface , caused by explosion at a fixed distance beneath the surface. The method (which is not described in Cook s book) is best applied by use of calibration curves employing as suitable standard a selected explosive. It has been claimed that the method is reproducible within 5 to 10% and gives data generally in fair accord with expectations from theoretical calculations, provided the depth and extent of the pond are sufficient to avoid shock reflections. In many cases, however, there was a necessity of taking into consideration the rate of evaporation of water at the gas bubble-water interface (Ref 17, p 37)... 

The French Test, called Essai dans la terre (test in the ground), may be considered as a modification of the Trauzl test. It is conducted as follows A lOOg cartridge of the test expl, provided with a No 8 detonator fuse, is buried underground in uniform soil to a depth of 1.5 meters. The soil is tamped by using dry, sifted sand. After expln of the cartridge, the diameter (D) and height of cavity (H) are measured in centimeters. The volume (V) of the cavity is calcd from the formula ... 

The modification of the chemical composition of polymer surfaces, and thus their wettability with chemical substances, can be realized in different ways electric discharges more commonly called Corona effect, oxidation by a flame, plasma treatment, UV irradiation and also UV irradiation under ozone atmosphere. Numerous studies have been devoted to the effects of these different treatments. More recently, Strobel et al. [204] compared the effects of these treatments on polypropylene and polyethylene terephthalate using analytical methods such as E.S.C.A., F.T.I.R., and contact angle measurements. They demonstrated that a flame oxidizes polymers only superficially (2-3 nm) whereas treatment realized by plasma effect or Corona effect permits one to work deeply in the polymer (10 nm). The combination of UV irradiation with ozone flux modifies the chemical composition of the polymers to a depth much greater than 10 nm, introducing oxygenated functions into the core of the polymer. 

Polyimide surface modification by a wet chemical process is described. Poly(pyromellitic dianhydride-oxydianiline) (PMDA-ODA) and poly(bisphenyl dianhydride-para-phenylenediamine) (BPDA-PDA) polyimide film surfaces are initially modified with KOH aqueous solution. These modified surfaces are further treated with aqueous HC1 solution to protonate the ionic molecules. Modified surfaces are identified with X-ray photoelectron spectroscopy (XPS), external reflectance infrared (ER IR) spectroscopy, gravimetric analysis, contact angle and thickness measurement. Initial reaction with KOH transforms the polyimide surface to a potassium polyamate surface. The reaction of the polyamate surface with HC1 yields a polyamic acid surface. Upon curing the modified surface, the starting polyimide surface is produced. The depth of modification, which is measured by a method using an absorbance-thickness relationship established with ellipsometry and ER IR, is controlled by the KOH reaction temperature and the reaction time. Surface topography and film thickness can be maintained while a strong polyimide-polyimide adhesion is achieved. Relationship between surface structure and adhesion is discussed. 

Here we report a wet surface modification of PMDA-ODA and poly-(bisphenyl dianhydride-para-phenylenediamine) (BPDA-PDA) with KOH or NaOH solution. The modified surfaces are identified with contact angles, XPS spectra and ER IR spectra. Polymer thickness and weight changes are also studied. The depth of modified layer is measured by a non-destructive technique using ER IR and ellipsometry. Relationship between surface structure and adhesion strength is discussed. 

The aim of this work is to give a better understanding of the role of the plasma on the surface modifications of the polypropylene. Different surface analysis techniques such as static SIMS and XPS have helped us to point out the chemical modifications of the plasma treated polymer. Auger depth profiles through the metallic coatings and their interfaces with the polypropylene have been performed in the case of both treated and non treated polypropylene. At last, Transmission Electron Microscopy (TEM) has been carried out and has allowed us to measure precisely the thickness of the metallic coating as well as to identify its growth process. 

Also, the method how the ablation parameters are acquired can have a pronounced influence on the results. The ablation rate can be defined either as the depth of the ablation crater after one pulse at a given fluence, or as the slope of a linear fit of a plot of the ablation depth versus the pulse number for a given fluence. Very different ablation rates can result from the two different measurement methods. This is especially the case for materials where ablation does not start with the first pulse, but after multiple pulses, or if the ablation crater depth after one pulse is too small to be measured. The process that occurs if ablation does not start with the first laser pulse is called incubation. It is related to physical or chemical modifications of the material by the first few laser pulses, which often results in an increase of the absorption at the irradiation wavelength [32,33], for example, the formation of double bonds in poly (methylmethacrylate) (PMMA). Incubation is normally observed only for polymers with low absorption coefficients at the irradiation wavelength. 

---