Shear-induced microstructures and dynamics processes of phospholipid cylinders in solutions

Abstract

Shear-induced microstructures and their corresponding dynamic processes are investigated for phospholipid cylinders in aqueous solution by dissipative particle dynamic simulation. Various phospholipid cylinders with cross-sections, which are formed under shear-free flow, are selected to examine the effects of shear flow on their structures and dynamic processes. Shear flow induces the transition from cylinders into vesicles at weak rate and the transition into vesicle–lamella mixtures with increased shear rate and lamella structures at the strong shear rate. Then, the average radius of gyration and shape factors of the polymer chains in the dynamic processes are discussed in detail. Results show that shear flow causes the structure of the polymer chains to be elongated along the shear direction, and the configuration of the polymer chain can be rapidly transformed into an ellipsoid structure under strong shear.

Interaction between Bottlebrush Polymers and Phospholipid Membranes in Solutions

“…The relaxation sustained a longer time in the strong adsorption cases compared with the weak adsorption case. The variance in the shape factor of a single bottlebrush molecule is different from those in previous works [ 42 ], in which the shape factor had undergone a process of first decreasing and then increasing, which is contrary to our results.…”

“…The gyration radius is an important parameter to understand the polymer size in the dynamic process [ 42 ]. The average radius of gyration can be defined as follows: …”

“…We plotted the shape factor as functions of time, as shown in Figure 3 , where the dotted lines are the fitting results for convenient analysis. When , the overall configuration tends to be rod-shaped; when , the bottlebrush polymer is close to a spherical structure; and when , a circular structure is formed [ 42 ]. The data showed that shape factors are about 0.15, indicating that the overall configuration of the bottlebrush molecule is between a spherical shape and a circular structure, so the shape of the polymer chain can be described as an ellipsoid, thus supporting the simulation results.…”

Predicting asymmetric phospholipid microstructures in solutions

“…This is evidence that shape factor hdi begins at 0.47 and then approaches 0.5 at the stable stage, a result that is similar to previous simulation results. 64 To observe the shape factor in detail, we drew the variation of the shape factor between 0s and 500s as the inserted part. By investigating the variation of the shape factor, we found that the asymmetric vesicle structure easily forms when the structure of the single chain exhibits spherical conformation.…”

Sensitive dependence on molecular interactions of length scales in sheared soft matter

“…When a complex fluid is subject to shear, a novel structure can emerge. Recent studies include for lamellar phases [17], colloids [18][19][20][21], colloidal gels [22][23][24], star polymers [25,26], biomolecules [27][28][29][30], biofluids [31], hydrogels [32], and graphene particles [33,34]. Neutron and x-ray scattering methods have proven valuable probes of the structure and rheology in soft matter [16,26,28,[35][36][37][38][39][40][41].…”