Small-Angle Neutron Scattering Studies of Chemically Cross-Linked Gelatin Solutions and Gels

Abstract

Small-angle neutron scattering measurements are reported for experiments performed on mixtures of gelatin and glutaraldehyde (GA) in the aqueous phase, where the gelatin concentration was fixed at 5% (w/v) and the GA concentration was varied from 1.25 × 10 -4 to 3 × 10 -3 % (w/v). Two length scales associated with this system were identified in both sol (60°C) and gel state (28°C). One of these, the correlation length ( ) or mesh size of the cross-linked network showed negligible dependence on temperature, but a scaling ∼ [GA] ν , where [GA] is the concentration of cross-linker GA, was observed with ν ) 0.33 ( 0.04 in the gel state. Other length scale associated was the size of inhomogeneities which showed no [GA] dependence but showed appreciable increase in size as the system transformed from a sol to gel state for all [GA]. Observations are discussed in the context of the results obtained from dynamic light scattering experiments performed earlier.

Testing Classical Approach to Polymer Solutions on SAXS Data of λ-Carrageenan, κ-Carrageenan and Methylcellulose Systems

“…This approach was namely originally developed and then also successfully applied mainly to the SANS data. [7][8][9][10][11][12][13][14][15] Even though there are some similar studies available also on the SAXS data nowadays, we still miss thorough systematic reports on such analysis of experimental SAXS data. The lack of such studies could be reasoned by the necessity of some additional considerations that must be dealt with the SAXS data, i.e.…”

“…For the evaluation and interpretation of the SAXS data we followed and adequately modified the so-called "classical approach" developed for the interpretation of similar SANS data on polymer solutions and gels. This approach was already extensively used and tested in the case of SANS on polymer solutions and simple gels [8][9][10][11][12][13][14][15] and recently already also on some SAXS data. [16][17][18][19] In the case of SAXS data one needs to account for the experimental broadening effects and correspondingly slightly modify the fitting scattering function.…”

Effect of cationic size on gelation temperature and properties of gelatin hydrogels

“…The ζ parameter is a measure of length of elastically active strands in the network while ξ g is the typical mesh size that characterizes the length scale of density fluctuations inside the gel medium. In a gelatin gel there is an assortment of networks bearing different dimensions as observed from small angle neutron scattering measurements [33]. The triple helical units (of length L) are the principal junction zones that constitute the main elastically active strands.…”

Supramolecular structure of methyl cellulose and lambda- and kappa-carrageenan in water: SAXS study using the string-of-beads model

“…(S2) given in Supporting Information, Appendix A. Good fits of this equation to the scattering data of some polymer gels can be observed in the literature (Geissler et al, 1997;Boualem Hammouda et al, 2004;Hoffmann et al, 2011;Horkay et al, 1998;Sharma et al, 2001;Shibayama et al, 2004), and apparently such a form factor contribution can be more-or-less expressed in the overall scattering intensity.…”

“…M. Hecht, Horkay, Schleger, & Geissler, 2002;Hoffmann et al, 2011;Horkay, Hecht, & Geissler, 1998;Sharma, Aswal, Goyal, & Bohidar, 2001;Shibayama, Isono, Okabe, Karino, & Nagao, 2004). Although some tests of this approach have already been made for SAXS data Dogsa, Kriechbaum, Stopar, & Laggner, 2005;Geissler et al, 1997), we were missing a more uniform, systematic study providing information about the quality of its performance on the SAXS data of polysaccharide systems with different structural behaviors.…”