Deuterated polystyrene film

Figure 7.12 Reflectivity calculated for a deuterated polystyrene film of thickness 500 A deposited on a Si substrate, to illustrate the effect of diffuse interfaces. Thin solid curve, o = 02 = 0 thin broken curve, o = 20A, 02 — 0 thick broken curve, o = 0, 02 — 20A.

Figure 4.15. The interfacial width between a thin deuterated polystyrene film and poly(methyl methacrylate), measured by neutron reflectometry. The d-PS relative molecular masses were 244 000 (+), 387 000 ( ), 641 000 ( ) and 400 000 (O and A) and the PMMA relative molecular masses were 365 000 (+, , and O) and 333 000 (A). After Sferrazza et al. (1997).

Experimeittal elastic recoil detection (ERD) spectrum from a thin, 200 A, deuterated polystyrene film (Composto et al. 2002)... 

Figure 1-20. IR spectra of normal atactic polystyrene and backbone-deuterated polystyrene films.

Fig. 5. Hydrogen depth profile of a deuterated polystyrene PS(D) film deposited on a protonated polystyrene PS(H) film on top of a silicon wafer as obtained by l5N-nuclear reaction analysis ( 5N-NRA). The small hydrogen peak at the surface is due to contamination (probably water) of the surface. The sharp interface between PS(D) and PS(H) is smeared by the experimental resolution (approx. 10 nm at a depth of 80 nm) [57], The solid line is a guide for the eye...

Bruder and Brenn (1992) studied the spinodal decomposition in thin films of a blend of deuterated polystyrene (dPS) and poly(styrene-co-4-bromostyrene) (PBrxS) by TOF-ERDA. They examined the effect of different substrates on the decomposition process. In one series of experiments, a solution of the polymers in toluene was spread on a silicon wafer to form a film of thickness 550 nm which was then heated in vacuum at 180°C for various times. 

Zink et al. used a blend of polystyrene (hPS) and its deuterated counterpart (dPS), both of molecular weight 1.95 x 106 (abbreviated 1.95 M). The average volume fraction (4>dPS) of deuterated polystyrene was 30%. The polymers were dissolved in toluene and spin cast on thin silicon wafers (about 10 x 10 mm), the resulting film thickness being about 300 nm. The samples were annealed at 245°C for 8 days, and the measurement of the resulting depth profiles was conducted by NRA using a monoenergetic 700 keV 3He beam. The nuclear reaction employed can be written ... 

A particularly striking observation was reported by Bruder and Brenn [72] for films of asymmetric blends of deuterated polystyrene (dPS) and poly(sty-rene-4-co-bromostyrene), PBrxS, with Ndps=5714, NPBxS =1660, using films of... 

Do D dPS dPS-PVP dL, dS specific value of diffusion coefficient 2.2.1 overall thin film thickness 3.2.1 deuterated polystyrene 2.2.1 diblock copolymers composed of dPS and PVP blocks 4.2.3 deuterated long (short) component of bimodal diblock mixture 4.2.4 ... 

Another type of dependence of effective interfacial width wD on film thickness D was observed [130] for immiscible mixture of deuterated polystyrene (dPS) and poly(methyl methacrylate) (PMMA) (at T TC) an increase, from wd=1.8(4) nm for a dPS layer thickness D=6 nm to wd(D=100 nm)=2.5(4) nm, follows the logarithmic dependence wD°clnD (intrinsic interfacial width w= 1.5 nm). This may reflect [6,224] long range forces acting from the external interfaces on the internal interface Ie(x,y). On the contrary, the relation wd D1/2 found for random olefines [121] corresponds [6,224] to short range forces. We note also that capillary waves in dPS/PMMA system were observed [130] already for the thickness-to-intrinsic width ratio D/w<85 ... 

In Figure 7.11 the curve calculated from (7.52) for the neutron reflectivity from a 500-A film of deuterated polystyrene deposited on a silicon substrate is compared with the exact result calculated from (7.29). The overall features are again well represented as long as 6 is much larger than the critical angle 0C, but the positions of the maxima and minima in the interference fringes deviate progressively more severely from the correct ones as 9 decreases toward 0C. 

Figure 7.16 shows the neutron reflectivity determined by Anastasiadis et al.15 with a sample in which a thin film of a diblock copolymer was deposited on a silicon substrate. The diblock copolymer, of molecular weight 100,000, consists of a block of deuterated polystyrene joined to a block of hydrogenous poly(methyl methacrylate) of about equal length and is therefore expected to organize itself into a lamellar... 

Figure 13 Surface-enhanced Raman spectra (SERS) obtained from thin films of blends of polystyrene and deuterated polystyrene before (A) and after annealing (B). Samples and conditions as in Fig. 9. 

Figure 3.24 shows a typical FRES spectrum, in this case from a blend of normal and deuterated polystyrene that after annealing shows some surface segregation of the deuterated component. The signal at the highest energy consists of deuterons recoiling from collisions at the surface of the film. Ions... 

Figure 4.18. Diffusion of deuterated polystyrene (d-PS) in normal polystyrene (h-PS), measured by forward recoil spectrometry (FReS). A 10-20 nm film of d-PS of relative molecular mass 225 000 was floated onto a 2 pm film of h-PS analysis of the deuterium depth profile shows that the d-PS layer was localised, to within the resolution of the technique, at the surface. After atmealing at 170 °C for 3600 s FReS revealed that substantial diffusion into the film had occurred the solid line is a fit to the solution of Fick s equation assmning that > = 8X10 cm s". After Mills et al. (1984).

Thin films of blended deuterated polystyrene (dPS) and poly(vinyl methyl ether) (PVME) were imaged as a fimction of the dPS PVME ratio. Near the critical composition of 35% dPS, an imdulating, spinodal-like structure was observed, whereas for compositions away from the critical mixture ratio, regular mounds or holes (< dPS < < crit and < dPS > (pent, respectively) were present. These variations were assigned to surface tension effects (120). Blends of PBD, SBR, isobutylene-brominated p-methylstyrene, PP, PE, natural rubber, and isoprene-styrene-isoprene block rubbers were imaged (Fig. 18). Stiff, styrenic phases and rubbery core-shell phases were evident as the authors utilized force-modulated afm to determine detailed microstructure of blends, including those with fillers such as carbon-black and silica (121). 

Fig. 6. The radius of gyration of deuterated polystyrene in a thin film normalized to its radius of gyration in the bulk as a function of film thickness that is also normalized to the radius of gyration of the polymer in the bulk. Mw = 270 K, = 650 K. Reprinted...

Experiments involving relaxation of centrally deuterated polystyrene chains in a higher molecular weight matrix recently provided support for the minor chain reptation model.Using infrared dichroism studies of step-strained PS films, the protonated chain-ends were found to relax faster than the centrally deuterated fraction. This is consistent with the MC model shown in Fig. 1(a) where the chain-ends first lose memory of their initial orientation. 

The mutual diffusion couples consisted of two films of deuterated polystyrene (D-PS). -protonated PXE blends which have a small difference in the volume fraction of d-PS (--lOj), from 2 in the 350 nm-thick top film to < )-j in the 2 pm-thick bottom film. The initial step function of the d-PS concentration profile was broadened by mutual diffusion at T in vacuum (<10" torr). The volume fraction versus depth profile of d-PS was... 

Ogawa H, Kanaya T, Nishida K, Matsuba G, Majewski JP, Watkins E. Time-resolved specular and off-specular neutron reflectivity measurements on deuterated polystyrene and poly( vinyl methyl ether) blend thin films during dewetting process. J Chem Phys 2009 131 104907. 

Figure 13 Volume fraction composition profiles for a thin film of deuterated polystyrene star polymer diffusing into a hydrogenous polystyrene star polymer film. Reprinted with permission from Clarke, N. Colley, F. R. Collins, S. A. etal. Macromolecules 2906,39,1290. Copyright 2006 American...

Surface characterization regarding other electron spectroscopies. To evidence specific attributes of HREELS to be compared to ESCA (XPS), UPS or AES ones, we chose to present (Figure 3) spectra recorded from polystyrenes (2). These thin film samples were made from normal and fully deuterated polymers. Immediately, it appears that HREELS is really capable of adding a new and unique dimension to electron surface analyses as ... 

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