Fig. 3: Forging the system by the application of a shear force to induce alignment.
a, The change in rheology and pH with time for a system containing l,d-2NapFF in the presence of urea, urease and GdL with no unidirectional shear. The inset photograph shows the sample after 16 h using the rheo-optics system. Throughout this figure, the lines and circles are colour coded to the coloured axis titles. b, The change in rheology and pH with time for a system containing l,d-2NapFF in the presence of urea, urease and GdL with unidirectional shear starting at 7 min and finishing at 100 min. The inset photograph shows the sample after 16 h using the rheo-optics system. c,d, Multi-scale analysis for a system with no shear alignment (c) and unidirectional shear (d) starting at 7 min and finishing at 100 min. Top: photographs of the sample at specific timepoints during the shearing process, indicated with an arrow. The dashed red line in the final image highlights the perimeter of the gel as it dried. Upper middle: time–space diagram of PLI using Herman’s algorithm to detect the presence of the Maltese cross pattern (green). Lower middle: time–space diagram of azimuthally integrated SAXS data with Herman’s orientation parameter (blue). Bottom: the imposed shear rate amplitude (oscillatory shear, c) or shear rate (steady shear, d). Scalar plot scattering intensity scales can be found in Supplementary Fig. 12. A full description of the calculations to obtain the orientation parameters can be found in Methods. In all cases, [l,d-2NapFF] = 5 mg ml−1, [urea] = 0.04 M, [urease] = 0.4 mg ml−1 and [GdL] = 14.3 mg ml−1. Ω, angular velocity of rotating geometry; ω, angular frequency; \({\dot{\gamma}}\), applied shear rate; P, orientation parameter; L, length of arc taken from each PLI frame; φ, azimuthal angle.
