## 3 Results and Discussion
### Isothermal Flow and Thixotropic Behavior  
The capacity of these matrixes to recover their strength after shearing input was studied by applying an increasing and decreasing shear rate cycle in a range from 0.1 to 100 s \({}^{-1}\) with step times of 5 s and tracking the changes in stress at 25 \({}^{\circ}\)C. This test gives a clear insight into the thixotropic behavior of lipidic matrixes. All ofthe samples showed a decrease of viscosity with increasing shear rates, suggesting a sensitive nature due to the weak interactions sustaining the 3D matrix network, such as van der Waals interactions and London dispersion forces. During the decreasing shear rate step, the samples showed a very small recovery of the structure (Table 4). This structure rearrangement led to a decrease in shear stress values after shifting back to low-shear condition (0.1 s \({}^{-1}\)). The BEW and OKW matrixes showed the largest recovery of 41.4 and 13%, respectively, whilst CRW and CLW  
\begin{table}
\begin{tabular}{c c c c c c c c c c c c} \hline \hline
**Lipidic** & **Critical** & **Critical** & **Dynamic** & **Average** & **Temperature** & **Angular Frequency G\({}^{\prime}\)** & **Angular Frequency** \\
**Matrix** & **Point** & **Stress** & **Yield** & **G\({}^{\prime}\)-G\({}^{\prime}\)\({}^{\matrixes presented the poorest recovery (<10%). This poor recovery is explained by the structure collapse into smaller clusters of aggregates as the matrix is sheared, but with the reduction of shearing, the re-establishment of these clusters into an ordered and cohesive network is hindered, since shear forces overcame the Brownian motion of suspended crystals [33].  
A creep test was subsequently conducted in order to confirm the above described shear results (Figure 3e). Thus, by applying a constant stress of 50 Pa for 25 s, weak matrixes, such as BEW and OKW, showed a large deformation, whilst the stiff CRW and CLW matrixes showed minimal change. Once that stress ceased, most matrixes suffered from an abrupt fall of deformation showing some tendency to recovery. In this case, the BEW matrix showed the largest recovery, whereas the CLW and CRW matrixes presented a low one. Thereby, the network structure in the last two matrixes is assumed to be a random agglomeration of oblongcrystalline particles, and the local bonding strength among the aggregates might be stronger in certain regions when compared to other regions due to localized crowding of aggregates. As the matrix is deformed over time, the structure breaks down into smaller clusters of aggregates flowing, and the restructuring of these clusters into a coherent network is avoided, because the shear force overcomes the Brownian motion.  
The sample flow profiles were fitted to the Herschel-Buckley model and Table 4 lists the results. This model can be used to define the degree of shear thinning (n \(<\) 1) or shear thickening (n \(>\) 1) of the matrix. Except for neat LEO, which showed a truly Newtonian behavior, all of the samples presented a pseudoplastic or shear thinning character (n \(<\) 1). The \"k\" parameter measures the thickness of the fluid, which is very close to the viscosity at very low shear rates. Interestingly, the degree of shear thinning was predominant for the CLW matrix, which also exhibited the largest consistency index (k) and yield stress for flow (\(\tau_{\mathrm{o}}\)). Conversely, the BEW and OKW matrixes were very weak in strength and, hence, showed the best flow and extensibility at low shear values. Interestingly, the OKW matrix was unstable under oscillatory strain sweep disrupting at a low strain. This matrix also showed a virtual absence in yield stress, indicating an almost immediate flow under applied shear. It is also important to note that, although the minimal stress for flow of this matrix was rather low, it was still appreciably high to prevent gravitational settling of the particle network.