SANS from Poly(ethylene oxide)/Water Systems

Abstract

The poly(ethylene oxide) (PEO)/water system is investigated using small-angle neutron scattering (SANS). This system associates to form hydrogen-bonded clusters at high enough concentrations. Two correlation lengths are observed: one long range representing cluster sizes and the other short range representing polymer chain correlations. Clusters are formed at a volume fraction of 4% hPEO in D 2O. An LCST transition is obtained between a mixed phase (through hydrogen bonding) and a demixed twophase region. Solvent deuteration is seen to enhance hydrogen bonding. Deuteration of the polymer backbone is seen to enhance hydrophobic interactions. The average polymer contrast match method fails due to the isotopic dependence of specific interactions. Pressure was seen to lower the LCST by breaking hydrogen bonds. At even higher temperature (beyond the boiling point of water) a UCST transition was observed.

RETRACTED: Controlled Light Cross-Linking Technique to Prepare Healable Materials

“…Matsunaga et al [31] have applied the approach of utilizing the first two terms for the interpretation of small-angle neutron scattering data of tetra-arm PEG gels. We refer to their study and references therein [32] for a more detailed discussion of the scattering of polymeric gels as the most studied polymeric networks. During the fitting procedure, we found ambiguous values for δ 1 because it is larger than our limit of determination.…”

Small angle neutron scattering contrast variation reveals heterogeneities of interactions in protein gels

“…A classical contrast variation analysis fails as previously observed for hydrophilic polymer solutions like PEO 12 and polyacrylamide 23 solutions. However, a careful investigation of data evidences the formation of H-rich zones for samples prepared with deuterated solvents.…”

“…This exchange, which might entail non uniform labeling in the case of proteins 9 , has to be taken into account to quantitatively interpret small-angle neutron scattering data 8,10 . Deuteration of the solvent has been shown in particular to modify the temperature of phase transitions 11 , to induce the clusterization of polymers in solution 12 , and to modify the stability of proteins 29, 35, 36,13, due to a modification of the balance between intramolecular and hydration interactions 14 . Thus, when using deuterated solvent in a sample comprising proteins in order to enhance the contrast, one has to be aware of the possible alteration of the interactions at play and of the non-uniform labeling of the proteins, which might lead to misinterpretation of SANS data.…”

Small-angle neutron scattering on polymer gels: phase behavior, inhomogeneities and deformation mechanisms

“…The cross-symbols are the scattering intensity data for linear PEG chains in D 2 O observed by Hammouda et al 94,95 and are assigned to clustering of PEG chains by the association of end groups. Hence, it is deduced that the strong upturn in I(q)/(f 0 x 2 ) at low-qx for Figure 18 Pictures of Tetra-PEG-10K.…”