Vibrational spectra and conformation of polyethylene glycol complexed with calcium and magnesium chlorides

Vibrational spectroscopic studies of sol–gel derived physical and chemical bonded ORMOSILs

“…1 and 2 show the FT-IR and FT-Raman spectra, respectively, of the SiO 2 -PEG (a) sono gels, S1 and (b) classic gels, Cl with different concentration of PEG (MW = 400 g/mole), marked under parenthesis. The spectra of the pure SiO 2 and pure PEG (data not in the same scale) are also shown for direct comparison and found similar to earlier reported data [13][14][15][16][17][18][19][20][21][22][23], The spectra of classic gels was also found similar to that reported earlier for the identical system [6]. The assignment of important bands of SiO 2 -PEG along with its constituents, SiO 2 and PEG are listed in Table 2.…”

“…It also became shoulder for the sono gel, S3, as observed earlier [25,27,28], It is legitimate too. The application of PEG hinders the hydrolysis-condensation reactions of silica, which forms strained fourmembered siloxane rings instead of six-membered rings reducing the availability of silanol groups at the surface of the pores [25,26], The application of high concentration or high molecular weight of PEG also up shifted the m s (Si-OH) band indicating a decrease in the Si-O bond length, which is most probably due to the hydrogen bonding with the oxygen of ether groups or the terminal hydroxyl groups of PEG [22,23,26], According to Fidalgo and Ilharco [26], silanol group gives a distinct sharp m(OH) band at (a) $3740 cm À1 , if it is isolated, (b) between 3300 and 3740 cm À1 , if it is perturbed at the oxygen atom (donor), (c) $3300 cm À1 , if the perturbation occurs at the hydrogen atom (acceptor) and/or from adsorbed water, and (d) the perturbation at both the atoms results in m(OH) band at contiguous wave numbers originating a broad band. The residual ethanol also gives a m(OH) band at $3640 cm À1 .…”

“…The m s (Si-OH) band corresponding to the residual silanol groups well appeared at $960 cm À1 (FT-IR) and $980 cm À1 (Raman) for the xerogels: SI and Cl with 5-10 wt% of PEG [14][15][16][17][18][19][20][21][22][23][24][25][26][27][28], This peak was overlapped by the PEG peak (FT-IR) or disappeared (Raman) for the high concentration of PEG indicating a decrease in the residual silanol groups. It was also found decreased for the sono gel, S2.…”

RETRACTED: Spectroscopic investigation of collagen scaffolds impregnated with AgNPs coated by PEG/TX-100 mixed systems

“…Poly(ethylene) glycol is known to form complexes with metal halides, e.g., those of Ca 2+ and Mg 2+ [63] and of Hg 2+ [64]. Vibrational spectra of these complexes show two spectral features similar to those observed upon chemisorption of PEG on the Ag • surface (see Table 3): (i) splitting of bands in the 950-1200 cm −1 region and (ii) shifts of ı(C C O) and ı(C O C) bending modes in the 500-600 cm −1 region to somewhat higher frequencies with increase in PEG concentration from 0.3 to 0.9 mM.…”

Electrospinning of calcium phosphate-poly(D,L-lactic acid) nanofibers for sustained release of water-soluble drug and fast mineralization

“…Then, CaP sample with nanospherical structure was formed by the reaction between Ca 2+ ions and PO 4 3-ions. 37,38 The selected-area electron diffraction pattern indicated an amorphous crystal phase of the product ( Figure 2B). The XRD pattern of the nanosphere product showed no obvious diffraction peaks but a broad characteristic peak of the amorphous phase at around 2θ=30° ( Figure 2C), indicating an amorphous crystal phase which agrees well with the result of selected-area electron diffraction.…”