Advancing the computational methodology of rigid rod and semiflexible polymer systems: A new solution to the wormlike chain model with rod‐coil copolymer calculations

The equilibrium phase behavior of main-chain liquid-crystalline polymer brushes in good solvent is investigated using self-consistent field theory. The calculation assumes semi-dilute brushes, where the grafting density is sufficient to cause overlap among the polymers but low enough to allow the solvent to be treated implicitly. The polymers are modeled as semi-flexible worm-like chains with Maier-Saupe interactions. Previous calculations based on freely-jointed chains have predicted that extended brushes collapse into folded nematic brushes, as the liquid-crystalline interaction strength is increased. For the more sophisticated model of worm-like chains, which penalizes hairpin folds, we find that extended brushes become unstable with respect to tilting prior to the onset of folding. This implies that the brushes spontaneously collapse by a symmetry-breaking transition, where the chains tilt rather than fold.

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“…Nevertheless, this challenge can likely be overcome with new improved numerical methods. 58 We leave this for a future study.…”

Section: Discussionmentioning

confidence: 99%

“…When confronted with this problem, Tang et al resorted to solving the statistical mechanics of the single wormlike chain in w ( z , u ) using Monte Carlo simulations. Nevertheless, this challenge can likely be overcome with new improved numerical methods . We leave this for a future study.…”

Section: Discussionmentioning

confidence: 99%

Spontaneous Tilting Transition in Liquid-Crystalline Polymer Brushes

2019

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“…Instead of the perfect symmetrical phase diagram of the coil−coil diblocks, the disorder−lamella transition point in the phase diagram is moved from the coil volume fraction f = 0.5 to a range between f = 0.6 and f = 0.65, which is also consistent with previous studies about the effect of orientation interactions and the geometrical asymmetry on the phase behavior of the rod−coil system. 52,68,71,72 From χN − f phase diagram of rod−coil blocks in the case of low-orientation interaction, we can see that a double continuous network structure DG appears in spite of complicated structures caused by the geometrical asymmetry and the orientation interaction. In the part of f ≤ 0.6, with the increase of the rigid composition, the proportion of DG in the phase diagram is larger, which is in sharp contrast to the coil− coil system.…”

Section: ■ Results and Discussionmentioning

confidence: 93%

Target-Directed Design of Phase Transition Path for Complex Structures of Rod–Coil Block Copolymers

et al. 2019

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We apply the string method to the self-consistent mean-field theory framework of the rod–coil block copolymer system to calculate the minimum energy pathways in the rearrangement transitions of lamellae and cylinders with different orientations under certain epitaxial growth relationship. Metastable phases appearing in the reordering transition pathway tend to form the structure at low χN side of the order–order transition boundary compared with the initial phase. In particular, for complex network, metastable phases, such as single gyroid and perforated lamellae, need to select a rearrangement transition between lamellae or cylinders near the order–disorder transition boundary with the same epitaxial growth relationship but different orientations. It is confirmed that this strategy for obtaining complex metastable phases by rational design of rearrangement transition between specific phases in the phase diagram can be applied to a wide range of χN as well as the coil–coil block copolymer system. We further investigate the rearrangement transition behavior combining with the analysis of contribution from the free energy, entropy, degree of mixing between different blocks, and the average orientation degree of rods during the phase transitions. Based on this mechanism, we have developed a target-directed design strategy for constructing self-assembled metastable structures of rod–coil block copolymers.

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“…[2] Originally,these concepts were predominantly applied to common surfactants and lipids, [3] but their validity is by no means limited to such compounds,and polymeric assemblies, when in thermodynamic equilibrium, satisfy the same description. [6] When the latter form closed shells,they are called vesicles,or, for polymers,"polymersomes". [5] When the hydrophilic-to-hydrophobic block length ratio decreases the curvature energies become smaller and one first encounters spheres,then rods,and finally lamellae.…”

mentioning

confidence: 99%

“…[5] When the hydrophilic-to-hydrophobic block length ratio decreases the curvature energies become smaller and one first encounters spheres,then rods,and finally lamellae. [6] When the latter form closed shells,they are called vesicles,or, for polymers,"polymersomes". [7] Arather special case are assemblies formed by oppositely charged polymers.…”

mentioning

confidence: 99%

Functional Polyion Complex Vesicles Enabled by Supramolecular Reversible Coordination Polyelectrolytes

et al. 2019

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Reported here is an ew class of PICsomes (vesicles formed by polyelectrolyte complexation) in which the anionic/ neutral diblockc opolymer is replaced by an anionic, reversible,s upramolecular polyelectrolyte based on metal-ligand coordination. This supramolecular polyelectrolyte forms exclusively inside the wall of the assembly,a nd therefore selfadjusts its length to that of the cationic blockp rovided. Moreover,t he supramolecular coordination polyelectrolytes introduce new and tunable properties and functions associated with the specific metal. As ap roof-of-concept Mn-based PICsomes were prepared and displayhigh magnetic relaxivity, as well as enhanced contrast in in vitro magnetic resonance imaging tests.The simplicity of our approach, together with the new functions derived from the metal ions,d emonstrates arobust strategy for the preparation of avariety of PICsomes with well-defined and tunable structures and properties.

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Advancing the computational methodology of rigid rod and semiflexible polymer systems: A new solution to the wormlike chain model with rod‐coil copolymer calculations

Cited by 6 publications

References 79 publications

Spontaneous Tilting Transition in Liquid-Crystalline Polymer Brushes

Spontaneous Tilting Transition in Liquid-Crystalline Polymer Brushes

Target-Directed Design of Phase Transition Path for Complex Structures of Rod–Coil Block Copolymers

Functional Polyion Complex Vesicles Enabled by Supramolecular Reversible Coordination Polyelectrolytes

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