Formation of Ionomer Microparticles via Polyelectrolyte Complexation

Abstract

Developing strategies for assembling ionic polymers into nanoaggregates with desired properties confers effective routes for the fabrications of functional materials. In dilute aqueous solutions, ionomers (composed of a hydrophobic backbone chain and grafted anionic pendant segments) normally self-assemble into small and dispersed clusters due to the electrostatic repulsions. Using coarse-grained molecular dynamics simulations, we develop a simple, convenient, but novel approach for fabricating large ionomer microparticles in dilute aqueous solutions. We demonstrate that added cationic polyelectrolytes (PEs) could electrostatically bind the dispersed ionomers and trigger their selfassembly into microparticles composed of a hydrophobic core and an anionic shell. The size of the microparticles could be precisely controlled by adjusting the concentration and chain length of the binding PEs. Furthermore, bare microparticles can be obtained through PE desorption in saline solution. We examine the mechanical and thermodynamic stability of the ionomer microparticle and its shape-memory nature in response to external force and temperature. Moreover, our simulations on electrophoresis reveal that a mobility reversal of the microparticles occurs due to overcharging of the binding PE. This work contributes to the development of novel strategies to fabricate smart polymer aggregates with predesigned structures and functions.

Structures of cationic and anionic polyelectrolytes in aqueous solutions: the sign effect

“…An interesting case would be the PE solutions at the overlap concentrations, at which the monomer concentration can be estimated as c 0 m ∼ N p /[4π( R g ) 3 /3] ∼ 6.8 [M] in our study. 10 In Fig. 6(a) and (b), we provide the typical simulation snapshots of flexible cationic and anionic PEs in an aqueous solution at σ ci = 3.250 [Å] with the monomer concentration of 6.7 [M].…”

“…1, following the derivation of our prior works and other previous studies. 10,22,24,55–66 The ions and PEs considered in this study are all hydrophilic.…”

“…Due to their significance in many areas of science and technological applications, polyelectrolytes have been the focus of extensive studies for decades. 5–10…”

Controllable Transition Metal-Directed Assembly of [Mo2O2S2]2+ Building Blocks into Smart Molecular Humidity-Responsive Actuators

“…To fundamentally comprehend the mechanism for humidity actuation process at the molecular level, we further employ MD simulation to study the adsorption of water molecules in and around a single { Bi 8 Mo 48 } cluster and in the Bi 8 Mo 48 -PDDA complex. Herein, the model is developed based on our previous simulations and other works, − and the simulations were performed using a large-scale atomic/molecular massively parallel simulator (LAMMPS); please see the details (Figure S22) in the Supporting Information. Figure a,b shows the top and side views of the simulation snapshots for water aggregation near a single { Bi 8 Mo 48 }, and Figure c,d displays the radial distribution functions of counterions [ g c/i ( r )] and water molecules [ g c/w ( r )] around { Bi 8 Mo 48 }.…”

Developing Dawson-Type Polyoxometalates Used as Highly Efficient Catalysts for Lignocellulose Transformation

“…Herein, the pp-ol and ionic species were coarse-grained as spherical beads and the simulations were performed in the canonical (NVT) ensemble through the Large-scale Atomic/Molecular Massively Parallel Simulator (LAMMPS) . The model was constructed based on our previous simulations and other studies; − please refer to the Supporting Information for the efficacy of the model (Figure S15) and simulation details. In Figure a,b, the representative simulation snapshots of the pp-ol/Bet + /Cl – and pp-ol/Ch + /Cl – solutions at the temperature of T ≈ 140 °C are displayed.…”