Poly Raman spectrum

FIGURE 10.11 Tip enhanced spontaneous Raman spectrum of DNA sample (poly(dA-dT)-poly(dA-dT)). The vibration at 1337 cm is employed as the target vibration. The corresponding vibration mode is illustrated in the figure. 

Structure of Poly iodine from the Resonance Raman Spectrum.Ill... 

Another good example of using Raman spectroscopy in the polymer industry is to investigate polymer blends. Raman microimages have been used to investigate the spatial distributions of the components in a blend of brominated poly(isobutylene-co-para-methylstyrene (BIMS) and cis-1-4-polybutadiene (BR) containing silica, zinc stearate, thiate, and other additives (21). A Raman spectrum of a blend is shown in Fig. 7-33. Specific bands can be assigned to BIMS, BR, silica, and zinc stearate. A 10 x 10 xm contour... 

Gerrard, D.L. and Maddams, W.F. (1981) Resonance Raman spectrum of degraded poly(vinyl chloride). 3. Background smdies. Macromolecules, 14 (5), 1356-62. 

Fig. 17. Raman spectrum of poly(a-aminoisobutyric acid) (Dwivedi el al., 1984). (A)...

There are few methods suitable for on-line chemical analysis of aerosol particles. Raman spectroscopy offers the possibility of identifying the chemical species in aerosol particles because the spectrum is specific to the molecular. structure of the material, especially to the vibrational and rotational modes of the molecules. Raman spectra have been obtained for individual micron-sized particles placed on surfaces, levitated optically or by an eiectrodynamic balance, or by monodisperse aerosols suspended in a flowing gas. A few measurements have also been made for chemically mixed and poly disperse aerosols. The Raman spectrum of a spherical particle differs from that of the bulk material because of morphology-dependent resonances that re.su It when the Raman scattered photons undergo Mie scattering in the particle. Methods have been developed for calculating the modified spectra (McNulty el al., 1980). 

Fig. 19 a) IR-ATR spectrum of poly(vinyl pyrrolidone) in water and b) Raman spectrum of the same sample... 

The Raman spectrum of an ordered, single-stranded or double-helical RNA shows an intense sharp band at 810-815 cm which shifts to near 795 cm upon disordering. This trmsition is clearly seen in the spectrum of poly(rA)poly(rU) in Fig. 15 while the same spectrum demonstrates the insensitivity of the 1100 cm feature to disruption of secondary structure. The intensity of the PO Raman mode remains constant at constant ionic strength. For RNA, at low ionic strength, the ratios of intensities of the bands at 851 and 1100 cm can be used to monitor the amount of secondary structure. 7(815)/( 7(1100) = 1.66 in completely ordered ribopolymers (double-helical or single-stranded) and 0.0 in completely disordered ribopolymers [50]. 

Raman spectrum of poly (vinyl chloride). Units are wavelengths cm" on the horizontal axis and energy on the vertical axis. 

Raman microspectroscopy studies indicate that the spectra from hardness impressions in SiC and those from the pristine surface outside the indentation area are significantly different [4, 134], This is illustrated in Figure 48 for a polycrystalline chemical-vapor deposited (CVD) 3C SiC film. The results for a single crystal 2H poly type of SiC are essentially the same [134], except for the extra line at 770 cm" in the Raman spectrum of pristine 2H SiC, related to the splitting of the TO(T) modes in hexagonal 2H as compared to the cubic 3C SiC [226]. This indicates that the deformation mechanism during indentation of SiC is independent of its microstructure prior to loading. Comparison of a typical spectrum... 

Study of the low-frequeney Raman spectrum of poly-L-lysine on both sides of the helix-to-eoil transition using ultrafast spectroseopy reveals the existenee of a broad band that ean be assigned to HB stretching vibrations between the solvent and the peptide. This band is found to shift depending upon the loeal stmeture of the peptide and refleets ehanges in the strength of the interaetions between water and the biopolymer. The frequeney of the band shows that these dynamies oeeur on the seale of 15-30 ps. 

Conducting poly thiophene (PTh)-SWCNTs composites were synthesized by the in situ chemical oxidative polymerization method.Using an excitation wavelength of 514 nm, the authors studied the pristine and the derived materials. The Raman spectrum for the SWCNT PTh composites is clearly an addition of the corresponding spectra of PTh and SWCNTs, demonstrating that SWCNTs served as templates in the formation of a co-axial nanostructure for the composites. ... 

In the work of Yi et the authors prepared a composite material by grafting a carbonizable polymer, poly(furfuryl alcohol) (PFA), to arylsulfonic acid (SA)-modified SWCNTs (Figure 9.6). The Raman spectrum of the PFA-SWCNT has similar features to those of the SA-SWCNT. The intensity ratio of the D-band to G-band was almost the same as that of the SA-SWCNT, suggesting that the PFA wrapping did not alter the hybridization of the carbon atoms within the SWCNT framework. They also observed that the RBMs of the PFA-SWCNT composite became even weaker than that of the SA-SWCNT. This would be expected if the attachment of the macromolecule would restrict the radial breathing of SWCNTs more than the SA group alone. 

Figure 4-10. Vibrational spectra of intact poly / -phenylene). (a) Raman spectrum taken with the 1064-nm line in powder sample (b) infrared spectrum in a KBr disk [83].

Raman spectrum of neutral poly( -phenyIene) is well explained by the effective-conjugation-coordinate model [95],... 

Figure 5-5. Raman spectrum of -poly(L-alanine). (From [89])...

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