PMMA film, depth profile

Fig. 2 shows one application of ATR depth profiling. In this case, ATR spectra were obtained as a function of angle of incidence from a polymethylmethacrylate (PMMA) film of thickness 0.5 p.m that was deposited onto a germanium hemi-cylinder [4]. The solid line represents the ATR spectrum of PMMA while the squares represent the film thickness that was recovered from the infrared spectra using four different bands. It can be observed that the recovered film thickness was very close to the measured thickness. 

Figure 2. Etch depth profile of PMMA film obtained with 248 nm ( ) excimer laser irradiation and that of polyimide film obtained with 248 nm(0) and 351 nm(0) excimer laser irradiation. Negative etch depth means permanent swelling. An error bar is included.

FTIR-ATR spectra of a laminate (PMMA/polyvinyl alcohol) were presented at different base layer thicknesses and different angles of incidence on a zinc selenide substrate. By varying the thickness of the PMMA barrier film, different effective penetration depths in the polyvinyl alcohol were achieved. These results agreed well with the calculated electric fields as a function of distance away from the substrate surface. The work provided the basis for depth profiling measurements to detect interfacial interactions. 18 refs. 

The use of an intennediate barrier layer to vary the penetration depth in an ATR experiment was used in probing concentration profiles away from the interface. Application of this technique in the study of PMMA/ PDMS graft copolymers deposited onto a copper oxide surface indicated a preferential presence of the siloxane component at the oxide interface a concentration gradient was observed to decrease with increasing distance into the bulk of the sample film (275). 

Figure 5 Left NR profiles for a 523.2 nm film of dPS-ft-PMMA symmetric, diblock copolymer as a function of the neutron momentum normal to the surface at the temperatures indicated. The scattering length density fitl/profiles as a function of depth z, where z= 0 is the air surface, shown in the insets were used to calculate the reflectivity profiles drawn as the solid lines in the figures. Right A log-log plot of the difference between T , and the bulk value of Tout, b as a function of film thickness using the value of Toot, b extrapolated from the NR measurements. Reproduced with permission from Menelle, A. Russell, T. P. Anastasiadis, S. H. etal. Phys. Rev. Lett. 1992, 68,67. ...

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