Rheooptical response of rodlike chains subject to transient shear flow. 2. Two-color flow birefringence measurements on collagen protein

Abstract

NSF-CPE80-25833) and from the ARCO Foundation. In addition, we thank Professor G. Marrucci for his helpful discussion and the preprint of his paper.

Characterizing the Orientational and Network Dynamics of Polydisperse Nanofibers on the Nanoscale

“…shows the β parameter in eq 1 as a function of the nanofibre surface charges, obtained by comparing the length distribution with the contributions B 0 (L) inFigure 2.The β parameters found here are in the range 100 − 1000, i.e. slightly lower than the values reported by other experiments 19,24,25,34. They show a decreasing trend when the surface β parameter as a function of the surface charges of the different nanofibre samples.…”

“…Here β is a numerical factor, k B the Boltzmann constant, T the temperature, L * the entanglement length (see Supporting Information) and η the solvent viscosity. β has been predicted to be of order 1 − 10 24,25,34,36,37 but its magnitude has been found in the range of 10 3 − 10 4 by several experiments 25,26,34,36 and refined theories. 24,37 Results and discussion…”

“…Birefringence decays for polydisperse systems exhibits multiple time scales 25,26,29,34 as the diffusion coefficient strongly depends on the nanoparticle length L. Therefore, deconvoluting the birefringence decays B(t) allows to obtain the contribution, i.e. the relative orientation, B 0 (L) of the nanofibres of length L to the total birefringence signal B 0 before the flow is stopped.…”

“…However, as surface charges are highly correlated with length distributions, this trend can also be associated with length effects. Indeed, the value of β is known to be strongly dependent on the caging of the nanorods, 20,24,25,34,37,42,43 i.e. the entanglement in the network.…”

Development and Biochemical Characterization of Injectable Collagen

“…1). 20 Electron microscopy of this collagen preparation (molecules sprayed from acidic solution) revealed that it was approximately 80% monomeric and 13% dimeric with a very low level of higher aggregates 22,23 . The remaining 7% consisted of shortened fragments, which appeared to be bimodal in size distribution, half being about 1/4 and half about 3/4 the length of the native molecule (Fig.…”