https://doi.org/10.1140/epje/i2011-11062-3
Regular Article
Internal structures of agar-gelatin co-hydrogels by light scattering, small-angle neutron scattering and rheology
1
Polymer and Biophysics Laboratory, School of Physical Sciences, Jawaharlal Nehru University, 110 067, New Delhi, India
2
Solid State Physics Division, Bhaba Atomic Research Centre, 400 085, Mumbai, India
* e-mail: santinathsingh@yahoo.com
Received:
3
March
2011
Revised:
16
May
2011
Accepted:
30
May
2011
Published online:
27
June
2011
Internal structures of agar-gelatin co-hydrogels were investigated as a function of their volumetric mixing ratio, 
, 1.0 and 2.0 using dynamic light scattering (DLS), small-angle neutron scattering (SANS) and rheology. The degree of non-ergodicity ( 
, which was extracted as a heterodyne contribution from the measured dynamic structure factor data remained less than that of homogeneous solutions where ergodicity is expected (X = 1 . The static structure factor, I(q) , results obtained from SANS were interpreted in the Guinier regime (low-q , which implied the existence of 
250 nm long rod-like structures (double-helix bundles), and the power law (intermediate-q regions yielded 
, with 
= 2.3 , 1.8 and 1.6 for r = 0.5 , 1.0 and 2.0. This is indicative of the presence of Gaussian chains at low r , while at r = 2 there was a propensity of rod-shaped structures. The gel strength and transition temperatures measured from frequency sweep and temperature ramp studies were suggestive of the presence of a stronger association between the two biopolymer networks at higher r . The results indicate that the internal structures of agar-gelatin co-hydrogels were highly dependent on the volumetric mixing ratio.
© EDP Sciences, SIF, Springer-Verlag Berlin Heidelberg, 2011
