Can oppositely charged polyelectrolyte stars form a gel? A simulational study

Soft Matter ◽  
2021 ◽  
Author(s):  
Andrea Tagliabue ◽  
Jonas Landsgesell ◽  
Massimo Mella ◽  
Christian Holm
Keyword(s):  
Equimolar Mixture ◽  
Block Length ◽  
Ionic Bond ◽  
Bond Kinetics ◽  
Oppositely Charged

A Langevin MD study of an equimolar mixture of monodispersed oppositely charged di- block four-armed polyelectrolyte stars is presented.  We determine the minimal charged block length which results in gels and we study the ionic bond kinetics.

scholarly journals Can Oppositely Charged Polyelectrolyte Stars Form a Gel? A Simulational Study

2020 ◽  
Author(s):  
Andrea Tagliabue ◽  
Jonas Landsgesell ◽  
Massimo Mella ◽  
Christian Holm
Keyword(s):  
Pure Water ◽  
Polymer Concentration ◽  
Water Reservoir ◽  
Equilibrium Concentration ◽  
Thermal Fluctuations ◽  
Coarse Grained ◽  
Block Length ◽  
Implicit Solvent ◽  
Ionic Bonds ◽  
Oppositely Charged

We present a Langevin molecular dynamics study of an equimolar mixture of<br>monodispersed oppositely charged di-block four-armed polyelectrolyte stars. We use<br>an implicit solvent coarse-grained representation of the polyelectrolyte stars and varied<br>the length of the terminal charged blocks that reside on each arm. By varying the<br>polymer concentration we computed P-V diagrams and determined the free-swelling<br>equilibrium concentration with respect to a pure water reservoir as a function of the<br>charged block length. We investigate various structural properties of the resulting<br>equilibrium structures, like the number of ionic bonds, dangling arms, isolated stars,<br>and cluster sizes. The ionic bonds feature a broad distribution of the number of arms<br>involved and also display a distribution of net charges peaked around the neutral ionic<br>bond. Our main result is that for charged block length equal to 4 and 5 ionized beads<br>the resulting macro-aggregate spans the box and forms a network phase. Furthermore,<br>we investigated the dynamics of ionic bonds, and computed their lifetimes and turing dynamics. The bonds are weak enough to allow a network restructuring under<br>thermal fluctuations but are still strong enough to yield a stable gel phase.<br>

scholarly journals Can Oppositely Charged Polyelectrolyte Stars Form a Gel? A Simulational Study

2020 ◽  
Author(s):  
Andrea Tagliabue ◽  
Jonas Landsgesell ◽  
Massimo Mella ◽  
Christian Holm
Keyword(s):  
Pure Water ◽  
Polymer Concentration ◽  
Water Reservoir ◽  
Equilibrium Concentration ◽  
Thermal Fluctuations ◽  
Coarse Grained ◽  
Block Length ◽  
Implicit Solvent ◽  
Ionic Bonds ◽  
Oppositely Charged

We present a Langevin molecular dynamics study of an equimolar mixture of<br>monodispersed oppositely charged di-block four-armed polyelectrolyte stars. We use<br>an implicit solvent coarse-grained representation of the polyelectrolyte stars and varied<br>the length of the terminal charged blocks that reside on each arm. By varying the<br>polymer concentration we computed P-V diagrams and determined the free-swelling<br>equilibrium concentration with respect to a pure water reservoir as a function of the<br>charged block length. We investigate various structural properties of the resulting<br>equilibrium structures, like the number of ionic bonds, dangling arms, isolated stars,<br>and cluster sizes. The ionic bonds feature a broad distribution of the number of arms<br>involved and also display a distribution of net charges peaked around the neutral ionic<br>bond. Our main result is that for charged block length equal to 4 and 5 ionized beads<br>the resulting macro-aggregate spans the box and forms a network phase. Furthermore,<br>we investigated the dynamics of ionic bonds, and computed their lifetimes and turing dynamics. The bonds are weak enough to allow a network restructuring under<br>thermal fluctuations but are still strong enough to yield a stable gel phase.<br>

THE VALIDITY MULTIMEDIA INTERACTIVE BASES ANDROID ON IONIC BOND MATERIAL

2020 ◽  
Vol 4 (2) ◽  
pp. 63
Author(s):  
Muhammad Kharis Syarifuddin ◽  
Kusumawati Dwiningsih
Keyword(s):  
Construct Validity ◽  
Interactive Multimedia ◽  
Development Stage ◽  
Chemistry Teacher ◽  
Development Research ◽  
Ionic Bond ◽  
Design Development ◽  
Content Validation ◽  
Percentage Content ◽  
Validation Score

This research is aims to describe the validity of interactive multimedia based on Android in the ion bonding sub material. This research uses Thiagarajan's 4-D development research consisting of Define; Design; Development and Disseminate. However, this research is limited to the Development stage of Thiagarajan in Ibrahim (2014). Multimedia validity is reviewed from the aspect of content validity and construct validity. This multimedia was validated by 2 Unesa chemistry lecturers and 1 chemistry teacher with the research instrument used in the form of a multimedia validation sheet then the results of the validation resulted in a validation score. Based on data analysis, it can be concluded that android-based interactive multimedia on the ion bond sub-material is valid for use with percentage content validation and construct validity respectively 91.85% and 89.61% with highly valid criteria.

scholarly journals Calcium carbonate modified urea–formaldehyde resin adhesive for strength enhanced medium density fiberboard production

RSC Advances ◽  
2021 ◽  
Vol 11 (40) ◽  
pp. 25010-25017
Author(s):  
Li Lu ◽  
Yan Wang ◽  
Tianhua Li ◽  
Supeng Wang ◽  
Shoulu Yang ◽  
...  
Keyword(s):  
Calcium Carbonate ◽  
Urea Formaldehyde ◽  
Medium Density Fiberboard ◽  
Urea Formaldehyde Resin ◽  
Formaldehyde Resin ◽  
Medium Density ◽  
Ionic Bond ◽  
Resin Adhesive ◽  
Uf Resin ◽  
Modified Urea

Reactions between CaCO3 and CH2O2 during polycondensation of UF resin produce Ca2+. Ionic bond complexation binds Ca2+ with UF resin. The UF resin crystalline percentage decreases from 26.86% to 22.71%. IB strength of resin bonded fiberboard increases from 0.75 to 0.94 MPa.

scholarly journals Solubilization of Charged Porphyrins in Interpolyelectrolyte Complexes: A Computer Study

Polymers ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 502
Author(s):  
Karel Šindelka ◽  
Zuzana Limpouchová ◽  
Karel Procházka
Keyword(s):  
Dissipative Particle Dynamics ◽  
Water Soluble ◽  
Coarse Grained ◽  
Core Shell ◽  
Computer Study ◽  
Interpolyelectrolyte Complex ◽  
The Core ◽  
Porphyrin Derivatives ◽  
Oppositely Charged ◽  
Positively Charged

Using coarse-grained dissipative particle dynamics (DPD) with explicit electrostatics, we performed (i) an extensive series of simulations of the electrostatic co-assembly of asymmetric oppositely charged copolymers composed of one (either positively or negatively charged) polyelectrolyte (PE) block A and one water-soluble block B and (ii) studied the solubilization of positively charged porphyrin derivatives (P+) in the interpolyelectrolyte complex (IPEC) cores of co-assembled nanoparticles. We studied the stoichiometric mixtures of 137 A10+B25 and 137 A10−B25 chains with moderately hydrophobic A blocks (DPD interaction parameter aAS=35) and hydrophilic B blocks (aBS=25) with 10 to 120 P+ added (aPS=39). The P+ interactions with other components were set to match literature information on their limited solubility and aggregation behavior. The study shows that the moderately soluble P+ molecules easily solubilize in IPEC cores, where they partly replace PE+ and electrostatically crosslink PE− blocks. As the large P+ rings are apt to aggregate, P+ molecules aggregate in IPEC cores. The aggregation, which starts at very low loadings, is promoted by increasing the number of P+ in the mixture. The positively charged copolymers repelled from the central part of IPEC core partially concentrate at the core-shell interface and partially escape into bulk solvent depending on the amount of P+ in the mixture and on their association number, AS. If AS is lower than the ensemble average ⟨AS⟩n, the copolymer chains released from IPEC preferentially concentrate at the core-shell interface, thus increasing AS, which approaches ⟨AS⟩n. If AS>⟨AS⟩n, they escape into the bulk solvent.

scholarly journals A review of nanotechnology with an emphasis on Nanoplex

2015 ◽  
Vol 51 (2) ◽  
pp. 255-263
Author(s):  
Rupali Nanasaheb Kadam ◽  
Raosaheb Sopanrao Shendge ◽  
Vishal Vijay Pande
Keyword(s):  
Drug Delivery ◽  
Drug Delivery Systems ◽  
Drug Loading ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Conventional Drug ◽  
Anionic Drugs ◽  
Oppositely Charged ◽  
The Brain

<p>The use of nanotechnology based on the development and fabrication of nanostructures is one approach that has been employed to overcome the challenges involved with conventional drug delivery systems. Formulating Nanoplex is the new trend in nanotechnology. A nanoplex is a complex formed by a drug nanoparticle with an oppositely charged polyelectrolyte. Both cationic and anionic drugs form complexes with oppositely charged polyelectrolytes. Compared with other nanostructures, the yield of Nanoplex is greater and the complexation efficiency is better. Nanoplex are also easier to prepare. Nanoplex formulation is characterized through the production yield, complexation efficiency, drug loading, particle size and zeta potential using scanning electron microscopy, differential scanning calorimetry, X-ray diffraction and dialysis studies. Nanoplex have wide-ranging applications in different fields such as cancer therapy, gene drug delivery, drug delivery to the brain and protein and peptide drug delivery.</p>

scholarly journals Adsorption in Mixtures with Competing Interactions

Molecules ◽  
2021 ◽  
Vol 26 (15) ◽  
pp. 4532
Author(s):  
Marek Litniewski ◽  
Alina Ciach
Keyword(s):  
Short Range ◽  
Selective Adsorption ◽  
Similar Amount ◽  
Particle Interactions ◽  
Near Surface ◽  
Gas Density ◽  
Short Range Repulsion ◽  
Adsorbed Layers ◽  
Dynamics Simulations ◽  
Oppositely Charged

A binary mixture of oppositely charged particles with additional short-range attraction between like particles and short-range repulsion between different ones in the neighborhood of a substrate preferentially adsorbing the first component is studied by molecular dynamics simulations. The studied thermodynamic states correspond to an approach to the gas–crystal coexistence. Dependence of the near-surface structure, adsorption and selective adsorption on the strength of the wall–particle interactions and the gas density is determined. We find that alternating layers or bilayers of particles of the two components are formed, but the number of the adsorbed layers, their orientation and the ordered patterns formed inside these layers could be quite different for different substrates and gas density. Different structures are associated with different numbers of adsorbed layers, and for strong attraction the thickness of the adsorbed film can be as large as seven particle diameters. In all cases, similar amount of particles of the two components is adsorbed, because of the long-range attraction between different particles.

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