TY  - JOUR
A1  - Poghosyan, Armen H.
A1  - Arsenyan, Levon H.
A1  - Gharabekyan, Hrant H.
A1  - Koetz, Joachim
A1  - Shahinyan, Aram A.
T1  - Molecular dynamics study of poly(diallyldimethylammonium chloride) (PDADMAC)/sodium dodecyl sulfate (SDS)/ decanol/water systems
N2  - We have performed a 50 ns of molecular dynamics study of poly(diallyldimethylammonium chloride) (PDADMAC)/ sodium dodecyl sulfate (SDS)/decanol/water systems. The influence of the cationic polyelectrolyte on the anionic SDS- based lamellar liquid crystalline system was investigated. The main structural parameters have been calculated and compared with experimental data. We obtain two types of PDADMAC conformation, a more folded structure A and a structure B where the PDADMAC molecule is adsorbed at the anionic head groups of the surfactant molecules. The polyelectrolyte- induced coexistence of two lamellar phases at a concentration of 2-3% of PDADMAC is observed, which is in agreement with experimental findings.
Y1  - 2009
UR  - http://pubs.acs.org/journal/jpcbfk
U6  - https://doi.org/10.1021/Jp806289c
SN  - 1520-6106
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  - 
TY  - JOUR
A1  - Gharabekyan, Hrant H.
A1  - Koetz, Joachim
A1  - Poghosyan, Armen H.
T1  - A protonated L-cysteine adsorption on gold surface
BT  - a molecular dynamics study
JF  - Colloids and surfaces : an international journal devoted to the principles and applications of colloid and interface science ; A, Physicochemical and engineering aspects
N2  - The adsorption of protonated L-cysteine onto Au(111) surface was studied via molecular dynamics method. The detailed examination of trajectories reveals that a couple of picoseconds need to be strongly adsorbed at the gold surface via L-cysteine's sulfur and oxygen atoms. The average distances of L-cysteine's adsorbed sulfur and oxygen from gold plane are-2.7 angstrom and-3.2 angstrom, correspondingly. We found that the adsorption of L-cysteine takes place preferentially at bridge site with possibility of-82%. Discussing the conformation features of protonated L-cysteine, we consider that the most stable conformation of protonated L-cysteine is "reverse boat" position, where sulfur and oxygen pointed down to the gold surface, while the amino group is far from the gold surface.
KW  - MD simulations
KW  - gold surface
KW  - GOIP
KW  - l-cysteine
KW  - adsorption
KW  - protonation
Y1  - 2021
U6  - https://doi.org/10.1016/j.colsurfa.2021.127452
SN  - 0927-7757
SN  - 1873-4359
VL  - 629
PB  - Elsevier
CY  - Amsterdam
ER  -