TY  - JOUR
A1  - Poghosyan, Armen H.
A1  - Arsenyan, Levon H.
A1  - Shahinyan, Aram A.
A1  - Koetz, Joachim
T1  - Polyethyleneimine loaded inverse SDS micelle in pentanol/toluene media
JF  - Colloids and surfaces : an international journal devoted to the principles and applications of colloid and interface science ; A, Physicochemical and engineering aspects
N2  - An atomic scale molecular dynamics simulation (100 ns) was carried out to reveal the conformational features of a cationic polyelectrolyte, i.e., hyperbranched polyethyleneimine (PEI), inside of water-in-oil microemulsion droplets stabilized by the anionic sodium dodecyl sulfate surfactant (SDS) layer. Simulations show that the polymer reorients very quickly and is localized at the headgroup region, i.e., the polymer nitrogens are close to SDS sulfur atoms. In spite of the availability of surface roughness caused by the polymer, we track a stable inverse micelle during the production run. In overall, the obtained parameters are well compared with experimental findings. (C) 2016 Elsevier B.V. All rights reserved.
KW  - SDS inverse micelle
KW  - Polyethyleneimine
KW  - Molecular dynamics simulations
KW  - Microemulsions
Y1  - 2016
U6  - https://doi.org/10.1016/j.colsurfa.2016.07.018
SN  - 0927-7757
SN  - 1873-4359
VL  - 506
SP  - 402
EP  - 408
PB  - Elsevier
CY  - Amsterdam
ER  - 
TY  - JOUR
A1  - Poghosyan, Armen H.
A1  - Arsenyan, Levon H.
A1  - Antonyan, Lilit A.
A1  - Shahinyan, Aram A.
A1  - Koetz, Joachim
T1  - Molecular dynamics simulations of branched polyethyleneimine in water-in-heptanol micelles stabilized by zwitterionic surfactants
JF  - Colloids and surfaces : an international journal devoted to the principles and applications of colloid and interface science ; A, Physicochemical and engineering aspects
N2  - We have performed a 50 ns molecular dynamics simulation of a hyperbranched polymer, i.e. polyethyleneimine (PEI), inside inverse micelles formed with zwitterionic surfactants 3-(N, N-dimethyldodecylammoniio)-propansulfonate (SB) in heptanol. The runs were performed using the GROMACS simulation package. During simulation time the PEI molecule undergoes a conformational deformation and compaction. The radius of gyration of the PEI molecule finally located in the center of the water droplet is decreased from 3 nm to 1.7 nm. The unusual shrinking of the PEI molecule inside the micelle explains the extraordinary template effect of these microemulsions by making cadmium sulfide or gold clusters. (C) 2015 Elsevier B.V. All rights reserved.
KW  - Surfactant micelles
KW  - Molecular dynamics simulations
KW  - Polyethyleneimine
Y1  - 2015
U6  - https://doi.org/10.1016/j.colsurfa.2015.03.053
SN  - 0927-7757
SN  - 1873-4359
VL  - 479
SP  - 18
EP  - 24
PB  - Elsevier
CY  - Amsterdam
ER  - 
TY  - JOUR
A1  - Poghosyan, Armen H.
A1  - Arsenyan, Levon H.
A1  - Gharabekyan, Hrant H.
A1  - Falkenhagen, Sandra
A1  - Koetz, Joachim
A1  - Shahinyan, Aram A.
T1  - Molecular dynamics simulations of inverse sodium dodecyl sulfate (SDS) micelles in a mixed toluene/pentanol solvent in the absence and presence of poly(diallyldimethylammonium chloride) (PDADMAC)
JF  - Journal of colloid and interface science
N2  - We have performed a 15 ns molecular dynamics simulation of inverse sodium dodecyl sulfate (SDS) micelles in a mixed toluene/pentanol solvent in the absence and presence of a cationic polyelectrolyte, i.e. poly(diallyldimethylammonium chloride) (PDADMAC). The NAMD code and CHARMM force field were used. During the simulation time, the radii of SOS inverse micelles changed and the radii of the water droplets have been calculated. The behavior of SDS hydrocarbon chains has been characterized by calculating the orientation order parameter and the chain average length. The water droplet properties (water flow, water molecules displacement) have been examined. In summary the MD simulations indicate a more rigid and ordered surfactant film due to the formation of a polyelectrolyte palisade layer in full agreement with the experimental findings, e.g. the viscosity increase and shift of the percolation boundary.
KW  - Surfactant micelles
KW  - Molecular dynamics simulations
KW  - SDS
Y1  - 2011
U6  - https://doi.org/10.1016/j.jcis.2011.01.091
SN  - 0021-9797
VL  - 358
IS  - 1
SP  - 175
EP  - 181
PB  - Elsevier
CY  - San Diego
ER  -