Shear induced ordering in branched living polymer solutions

Thakur, Snigdha; Prathyusha, K. R.; Deshpande, Abhijit P.; Laradji, Mohamed; Kumar, P. B. Sunil

doi:10.1039/b915339j

Cited by 15 publications

(21 citation statements)

References 27 publications

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“…The extra V 4 potential and the modified terms in Eqn. 2 improves upon the previous potentials used to model equilibrium polymers [50][51][52][53]. Figure 2a and 2b shows snapshots of 6000 and 7500 monomers, respectively, in a 30 × 30 × 60σ 3 simulation box after the system is equilibrated using Monte Carlo (MC) Metropolis algorithm.…”

mentioning

confidence: 96%

Hierarchical self-assembly: Self-organized nanostructures in a nematically ordered matrix of self-assembled polymeric chains

Mubeena

Chatterji

2015

Phys. Rev. E

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We report many different nano-structures which are formed when model nano-particles of different sizes (diameter σn) are allowed to aggregate in a background matrix of semi-flexible self assembled polymeric worm like micellar chains. The different nano-structures are formed by the dynamical arrest of phase-separating mixtures of micellar monomers and nano-particles. The different morphologies obtained are the result of an interplay of the available free volume, the elastic energy of deformation of polymers, the density (chemical potential) of the nano-particles in the polymer matrix and, of course, the ratio of the size of self assembling nano-particles and self avoidance diameter of polymeric chains. We have used a hybrid semi-grand canonical Monte Carlo simulation scheme to obtain the (non-equilibrium) phase diagram of the self-assembled nano-structures. We observe rod-like structures of nano-particles which get self assembled in the gaps between the nematically ordered chains as well as percolating gel-like network of conjoined nanotubes. We also find a totally unexpected interlocked crystalline phase of nano-particles and monomers, in which each crytal plane of nanoparticles is separated by planes of perfectly organized polymer chains. We identified the condition which leads to such interlocked crystal structure. We suggest experimental possibilities of how the results presented in this paper could be used to obtain different nano-structures in the lab. There is persistent interest in the controlled self assembly and growth of nano-structures of predefined morphology and size starting from small constituent nanoparticles (NP) . A separate non-alligned interest of physicists is in the formation and properties of topological defects when large particles (large compared to the size and spacing between nematogens) are introduced in ordered liquid crystalline nematic and smectic phases [29][30][31][32][33][34][35][36][37][38][39][40][41]. Recents experiments have also explored the self organization of nano-particles in a background matrix of nematically ordered micellar phase, but constraints in the choice of size of NPs led to the following two scenarios: small NPs of 2 − 3 nm diameter pervade the nematic chains themselves and form a dispersion/solution, whereas, larger NPs of size 8 − 26 nm get expelled by the elastic energy of ordered nematic phases and aggregate at the grain boundaries between nematic domains [42][43][44]. The distance between adjacent nematic chains was 5.7 nm in the experiments.Our present study spans across these two different research domains and we use computer simulations to investigate the heirarchical self assembly of NPs in the free volume between parallel chains of nematically ordered worm-like micelles (WM). The micellar polymers are selfassembled themselves from monomeric beads and have a length and size distribution controlled by monomer density and temperature [45][46][47]. In a computer simulation, we are able to systematically vary the diameter, chemical potential of the spher...

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confidence: 96%

Hierarchical self-assembly: Self-organized nanostructures in a nematically ordered matrix of self-assembled polymeric chains

Mubeena

Chatterji

2015

Phys. Rev. E

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“…In particular, MPCD has been used extensively in the last decade to simulate the dynamics and flow fields of various nano-and microswimmers like a Taylor sheet [9], artificial nano-and microswimmers [10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25], sperm cells, flagella, cilia, and self-propelled rods [26][27][28][29][30][31][32][33][34][35][36], dumbbell swimmers [37], swimming bacteria [38][39][40], and the complicated motion of the parasite African Trypanosome [41][42][43] and bacterial swarmer cells [44]. At present a very popular spherical model swimmer is the so-called squirmer.…”

Section: Introductionmentioning

confidence: 99%

Simulating squirmers with multiparticle collision dynamics

Zöttl

Stark

2018

Eur. Phys. J. E

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Multiparticle collision dynamics is a modern coarse-grained simulation technique to treat the hydrodynamics of Newtonian fluids by solving the Navier-Stokes equations. Naturally, it also includes thermal noise. Initially it has been applied extensively to spherical colloids or bead-spring polymers immersed in a fluid. Here, we review and discuss the use of multiparticle collision dynamics for studying the motion of spherical model microswimmers called squirmers moving in viscous fluids.

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“…Our aim is to develop a spherically symmetric model potential such that particles interacting by the potential self-assemble to linear equilibrium polymeric chains which are semiflexible; real life examples of such self assembled polymeric chains is worm-like micelles [20][21][22]. There exists quite a few coarse-grained models which describe self-assembling micellar chains [6,[23][24][25][26][27][28][29][30][31][32][33][34]. Some use suitable rate constants to model joining and breaking of bonds between effective bead-spring monomers where only 2 bonds are allowed per monomer [25][26][27][28][29][30][31].…”

Section: Introductionmentioning

confidence: 99%

“…Other models have effective potentials for self assembly of particles into polymeric chains, where semiflexibility is incorporated by suitable angle dependent potentials [24,32]. Branching or cluster formation is prevented by suitable choice of parameters of 3-body or 4 body potentials [6,[32][33][34]. The use of 3-body or 4-body potentials is cumbersome and computationally expensive, espcially when one wants to model systems of long chains to study interesting phenomenon such as shear banding [35][36][37][38].…”

Section: Introductionmentioning

confidence: 99%

Self assembled linear polymeric chains with tuneable semiflexibility using isotropic interactions

Abraham

Chatterji

2018

The Journal of Chemical Physics

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We propose a two-body spherically symmetric (isotropic) potential such that particles interacting by the potential self-assemble into linear semiflexible polymeric chains without branching. By suitable control of the potential parameters, we can control the persistence length of the polymer and can even introduce a controlled number of branches. Thus we show how to achieve effective directional interactions starting from spherically symmetric potentials. The self-assembled polymers have an exponential distribution of chain lengths akin to what is observed for worm-like micellar systems. On increasing particle density, the polymeric chains self-organize to an ordered line-hexagonal phase where every chain is surrounded by six parallel chains, the transition is first order. On further increase in monomer density, the order is destroyed and we get a branched gel-like phase. This potential can be used to model semi-flexible equilibrium polymers with tunable semiflexibility and excluded volume. The use of the potential is computationally cheap and hence can be used to simulate and probe equilibrium polymer dynamics with long chains. The potential also gives a plausible method of tuning colloidal interactions in experiments such that one can obtain self-assembling polymeric chains made up of colloids and probe polymer dynamics using an optical microscope. Furthermore, we show how a modified potential leads to the observation of an intermediate nematic phase of self-assembled chains in between the low density disordered phase and the line-ordered hexagonal phase.

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Shear induced ordering in branched living polymer solutions

Cited by 15 publications

References 27 publications

Hierarchical self-assembly: Self-organized nanostructures in a nematically ordered matrix of self-assembled polymeric chains

Hierarchical self-assembly: Self-organized nanostructures in a nematically ordered matrix of self-assembled polymeric chains

Simulating squirmers with multiparticle collision dynamics

Self assembled linear polymeric chains with tuneable semiflexibility using isotropic interactions

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