Zooming in: Structural Investigations of Rheologically Characterized Hydrogen-Bonded Low-Methoxyl Pectin Networks.
Self-assembled hydrogen-bonded networks of the polysaccharide pectin, a mechanically functional component of plant cell walls, have been of recent interest as biomimetic exemplars of physical gels, and the microrheological and strain-stiffening behaviors have been previously investigated. Despite this detailed rheological characterization of preformed gels, little is known about the fundamental arrangement of the polymers into cross-linking junction zones, the size of these bonded regions, and the resultant network architecture in these hydrogen-bonded materials, especially in contrast to the plethora of such information available for their well-known calcium-assembled counterparts. In this work, in concert with pertinent rheological measurements, an in-depth structural study of the hydrogen-bond-mediated gelation of pectins is provided. Gels were realized by using glucona-delta-lactone to decrease the pH of solutions of pectic polymers that had a (blockwise) low degree of methylesterification. Small-angle X-ray scattering and transmission electron microscopy were utilized to access structural information on length scales on the order of nanometers to hundreds of nanometers, while complementary mechanical properties were measured predominantly using small amplitude oscillatory shear rheology.
Institute of Fundamental Sciences, Massey University , Palmerston North 4474, New Zealand.|The Macdiarmid Institute for Advanced Materials and Nanotechnology, Wellington 6140, New Zealand.
Bradley W
BW
Mansel
National Tsing-Hua University, Hsin-Chu 30013, Taiwan.|National Synchrotron Radiation Research Centre, Hsin-Chu 30076, Taiwan.
Che-Yi
CY
Chu
CSIRO, Australian Animal Health Laboratory , Geelong 3220, Australia.
Andrew
A
Leis
The University of Auckland, Auckland 1010, New Zealand.
Yacine
Y
Hemar
National Tsing-Hua University, Hsin-Chu 30013, Taiwan.
Hsin-Lung
HL
Chen
CSIRO Food and Nutrition, Werribee 3030, Australia.
Leif
L
Lundin
Institute of Fundamental Sciences, Massey University , Palmerston North 4474, New Zealand.|The Macdiarmid Institute for Advanced Materials and Nanotechnology, Wellington 6140, New Zealand.
Martin A K
MA
Williams
D006863:Hydrogen-Ion Concentration