Entangled triblock copolymer gel: Morphological and mechanical properties

Abstract

The morphological and mechanical properties of entangled ABA triblock copolymer gels, where solvent were selective to the midblock, were studied as a function of polymer concentration using a novel dissipative particle dynamics model which includes a modified segmental repulsive potential that restricts chain crossing. Morphological properties, such as micelle size, distance between micelles, and the bridge fraction, were calculated as a function of concentration. Although the micelle size was shown to have a strong dependence on concentration, the bridge fraction and distance between micelles were shown to plateau at moderate concentrations. Deformation under uni-axial tension was also performed to extract the cross-link and entanglement contribution to the elastic modulus. Scaling results qualitatively agree with other theoretical predications.

Dissipative Particle Dynamics Study of SWCNT Reinforced Natural Rubber Composite System: An Important Role of Self‐Avoiding Model on Mechanical Properties

“…The definition of tensile stress (σ ij ) and strain (ε) in this simulation followed Chantawansri et al During the affine uniaxial deformation in the x direction, the pressure anisotropy was monitored and used to calculate the Young's modulus following a scheme employed by Thomson et al The net stress corresponding to the elongation tensile was evaluated from the following expressionwhere Δ P = P deformation – P equilibrium and denotes the specified net pressure change as the box was deformed during the NVT simulation. The Open Visualization Tool (OVITO) molecular graphic viewer was used to visualize the nanocomposite arrangement during the elongation …”

“…The DPD with mSRP (DPD/mSRP) model was used to investigate the properties of very large polymeric systems . Chantawansri et al used DPD/mSRP to study the morphology and the effect of polymer chain length on the mechanical properties of entangled triblock copolymer gels . When the mSRP is not used, the role of entanglement in the stress–strain curve cannot be correctly observed, and only the effect of crosslinking can be seen.…”

Tough and Self‐Recoverable Thin Hydrogel Membranes for Biological Applications

“…The lower C P limit (0.1) is close to the entanglement concentration of this block copolymer in DMF (data not shown). Below the entanglement concentration, the triblock copolymers form flower‐micelle structures in which two endblocks are located in the same micelle rather than bridged between two micelles . The upper limit (0.25) is related to the high viscosity of the solution, above which nonuniform gel membranes were observed during spin coating due to Marangoni‐like instability .…”

Salt Responsive Morphologies of ssDNA‐Based Triblock Polyelectrolytes in Semi‐Dilute Regime: Effect of Volume Fractions and Polyelectrolyte Length

“…Chain bridges between the micelles in the network are considered to be the elastically active chains, the number of which is proportional to elastic modulus of polymer networks . The modulus has contributions from both cross‐links ( G c ) and entanglements ( G e ) in neutral triblock copolymer gels: G = G c + G e and G c ≈ f bridge f volume , where f bridge is percentage of bridge chains and f volume is the volume fraction of copolymers. The cross‐link contribution dominates for polyelectrolyte triblock gels, since the entanglement is not likely to happen due to the electrostatic repulsion between polyelectrolyte blocks.…”