@article{LiebigSarhanPrietzeletal.2016,
  author    = {Liebig, Ferenc and Sarhan, Radwan Mohamed and Prietzel, Claudia Christina and Reinecke, Antje and Koetz, Joachim},
  title     = {"Green" gold nanotriangles: synthesis, purification by polyelectrolyte/micelle depletion flocculation and performance in surface-enhanced Raman scattering},
  series = {RSC Advances},
  volume    = {6},
  journal   = {RSC Advances},
  publisher = {Royal Society of Chemistry},
  address   = {Cambridge},
  issn      = {2046-2069},
  doi       = {10.1039/c6ra04808k},
  pages     = {33561 -- 33568},
  year      = {2016},
  abstract  = {The aim of this study was to develop a one-step synthesis of gold nanotriangles (NTs) in the presence of mixed phospholipid vesicles followed by a separation process to isolate purified NTs. Negatively charged vesicles containing AOT and phospholipids, in the absence and presence of additional reducing agents (polyampholytes, polyanions or low molecular weight compounds), were used as a template phase to form anisotropic gold nanoparticles. Upon addition of the gold chloride solution, the nucleation process is initiated and both types of particles, i.e., isotropic spherical and anisotropic gold nanotriangles, are formed simultaneously. As it was not possible to produce monodisperse nanotriangles with such a one-step procedure, the anisotropic nanoparticles needed to be separated from the spherical ones. Therefore, a new type of separation procedure using combined polyelectrolyte/micelle depletion flocculation was successfully applied. As a result of the different purification steps, a green colored aqueous dispersion was obtained containing highly purified, well-defined negatively charged flat nanocrystals with a platelet thickness of 10 nm and an edge length of about 175 nm. The NTs produce promising results in surface-enhanced Raman scattering.},
  language  = {en}
}
@article{DolyaRojasKosmellaetal.2013,
  author    = {Dolya, Natalya and Rojas, Oscar and Kosmella, Sabine and Tiersch, Brigitte and Koetz, Joachim and Kudaibergenov, Sarkyt},
  title     = {"One-Pot" in situ frmation of Gold Nanoparticles within Poly(acrylamide) Hydrogels},
  series = {Macromolecular chemistry and physics},
  volume    = {214},
  journal   = {Macromolecular chemistry and physics},
  number    = {10},
  publisher = {Wiley-VCH},
  address   = {Weinheim},
  issn      = {1022-1352},
  doi       = {10.1002/macp.201200727},
  pages     = {1114 -- 1121},
  year      = {2013},
  abstract  = {This paper focuses on two different strategies to incorporate gold nanoparticles (AuNPs) into the matrix of polyacrylamide (PAAm) hydrogels. Poly(ethyleneimine) (PEI) is used as both reducing and stabilizing agent for the formation of AuNPs. In addition, the influence of an ionic liquid (IL) (i.e., 1-ethyl-3-methylimidazolium ethylsulfate) on the stability of the nanoparticles and their immobilization in the hydrogel is investigated The results show that AuNPs surrounded by a shell containing PEI and IL, synthesized according to the one-pot approach, are much better immobilized within the PAAm hydrogel. Hereby, the IL is responsible for structural changes in the hydrogel as well as the improved stabilization and embedding of the AuNPs into the polymer gel matrix.},
  language  = {en}
}
@article{LiebigHenningSarhanetal.2018,
  author    = {Liebig, Ferenc and Henning, Ricky and Sarhan, Radwan Mohamed and Prietzel, Claudia Christina and Bargheer, Matias and Koetz, Joachim},
  title     = {A new route to gold nanoflowers},
  series = {Nanotechnology},
  volume    = {29},
  journal   = {Nanotechnology},
  number    = {18},
  publisher = {IOP Publ. Ltd.},
  address   = {Bristol},
  issn      = {0957-4484},
  doi       = {10.1088/1361-6528/aaaffd},
  pages     = {8},
  year      = {2018},
  abstract  = {Catanionic vesicles spontaneously formed by mixing the anionic surfactant bis(2-ethylhexyl)sulfosuccinate sodium salt with the cationic surfactant cetyltrimethylammonium bromide were used as a reducing medium to produce gold clusters, which are embedded and well-ordered into the template phase. The gold clusters can be used as seeds in the growth process that follows by adding ascorbic acid as a mild reducing component. When the ascorbic acid was added very slowly in an ice bath round-edged gold nanoflowers were produced. When the same experiments were performed at room temperature in the presence of Ag+ ions, sharp-edged nanoflowers could be synthesized. The mechanism of nanoparticle formation can be understood to be a non-diffusion-limited Ostwald ripening process of preordered gold nanoparticles embedded in catanionic vesicle fragments. Surface-enhanced Raman scattering experiments show an excellent enhancement factor of 1.7 . 10(5) for the nanoflowers deposited on a silicon wafer.},
  language  = {en}
}
@article{GharabekyanKoetzPoghosyan2021,
  author    = {Gharabekyan, Hrant H. and Koetz, Joachim and Poghosyan, Armen H.},
  title     = {A protonated L-cysteine adsorption on gold surface},
  series = {Colloids and surfaces : an international journal devoted to the principles and applications of colloid and interface science ; A, Physicochemical and engineering aspects},
  volume    = {629},
  journal   = {Colloids and surfaces : an international journal devoted to the principles and applications of colloid and interface science ; A, Physicochemical and engineering aspects},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {0927-7757},
  doi       = {10.1016/j.colsurfa.2021.127452},
  pages     = {7},
  year      = {2021},
  abstract  = {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.},
  language  = {en}
}
@misc{LiebigHenningSarhanetal.2019,
  author    = {Liebig, Ferenc and Henning, Ricky and Sarhan, Radwan Mohamed and Prietzel, Claudia Christina and Schmitt, Clemens Nikolaus Zeno and Bargheer, Matias and Koetz, Joachim},
  title     = {A simple one-step procedure to synthesise gold nanostars in concentrated aqueous surfactant solutions},
  series = {Postprints der Universit{\"a}t Potsdam Mathematisch-Naturwissenschaftliche Reihe},
  journal   = {Postprints der Universit{\"a}t Potsdam Mathematisch-Naturwissenschaftliche Reihe},
  number    = {769},
  issn      = {1866-8372},
  doi       = {10.25932/publishup-43874},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-438743},
  pages     = {23633 -- 23641},
  year      = {2019},
  abstract  = {Due to the enhanced electromagnetic field at the tips of metal nanoparticles, the spiked structure of gold nanostars (AuNSs) is promising for surface-enhanced Raman scattering (SERS). Therefore, the challenge is the synthesis of well designed particles with sharp tips. The influence of different surfactants, i.e., dioctyl sodium sulfosuccinate (AOT), sodium dodecyl sulfate (SDS), and benzylhexadecyldimethylammonium chloride (BDAC), as well as the combination of surfactant mixtures on the formation of nanostars in the presence of Ag⁺ ions and ascorbic acid was investigated. By varying the amount of BDAC in mixed micelles the core/spike-shell morphology of the resulting AuNSs can be tuned from small cores to large ones with sharp and large spikes. The concomitant red-shift in the absorption toward the NIR region without losing the SERS enhancement enables their use for biological applications and for time-resolved spectroscopic studies of chemical reactions, which require a permanent supply with a fresh and homogeneous solution. HRTEM micrographs and energy-dispersive X-ray (EDX) experiments allow us to verify the mechanism of nanostar formation according to the silver underpotential deposition on the spike surface in combination with micelle adsorption.},
  language  = {en}
}
@article{LiebigHenningSarhanetal.2019,
  author    = {Liebig, Ferenc and Henning, Ricky and Sarhan, Radwan Mohamed and Prietzel, Claudia Christina and Schmitt, Clemens Nikolaus Zeno and Bargheer, Matias and Koetz, Joachim},
  title     = {A simple one-step procedure to synthesise gold nanostars in concentrated aqueous surfactant solutions},
  series = {RSC Advances},
  volume    = {9},
  journal   = {RSC Advances},
  publisher = {RSC Publishing},
  address   = {London},
  issn      = {2046-2069},
  doi       = {10.1039/C9RA02384D},
  pages     = {23633 -- 23641},
  year      = {2019},
  abstract  = {Due to the enhanced electromagnetic field at the tips of metal nanoparticles, the spiked structure of gold nanostars (AuNSs) is promising for surface-enhanced Raman scattering (SERS). Therefore, the challenge is the synthesis of well designed particles with sharp tips. The influence of different surfactants, i.e., dioctyl sodium sulfosuccinate (AOT), sodium dodecyl sulfate (SDS), and benzylhexadecyldimethylammonium chloride (BDAC), as well as the combination of surfactant mixtures on the formation of nanostars in the presence of Ag⁺ ions and ascorbic acid was investigated. By varying the amount of BDAC in mixed micelles the core/spike-shell morphology of the resulting AuNSs can be tuned from small cores to large ones with sharp and large spikes. The concomitant red-shift in the absorption toward the NIR region without losing the SERS enhancement enables their use for biological applications and for time-resolved spectroscopic studies of chemical reactions, which require a permanent supply with a fresh and homogeneous solution. HRTEM micrographs and energy-dispersive X-ray (EDX) experiments allow us to verify the mechanism of nanostar formation according to the silver underpotential deposition on the spike surface in combination with micelle adsorption.},
  language  = {en}
}
@article{Koetz2000,
  author    = {Koetz, Joachim},
  title     = {Adsorption von polyelektrolyten an kolloidalen Partikeln},
  isbn      = {3-8265-7819-8},
  year      = {2000},
  language  = {de}
}
@article{PoghosyanAdamyanShahinyanetal.2019,
  author    = {Poghosyan, Armen H. and Adamyan, Maksim P. and Shahinyan, Aram A. and Koetz, Joachim},
  title     = {AOT Bilayer Adsorption on Gold Surfaces},
  series = {The journal of physical chemistry : B, Condensed matter, materials, surfaces, interfaces \& biophysical chemistry},
  volume    = {123},
  journal   = {The journal of physical chemistry : B, Condensed matter, materials, surfaces, interfaces \& biophysical chemistry},
  number    = {4},
  publisher = {American Chemical Society},
  address   = {Washington},
  issn      = {1520-6106},
  doi       = {10.1021/acs.jpcb.8b11471},
  pages     = {948 -- 953},
  year      = {2019},
  abstract  = {A molecular dynamics study was done to reveal the adsorption properties of sodium dioctyl sulfosuccinate (AOT) bilayers on gold Au(111) surfaces. Examining the rotational mobility of AOT molecules, we track that the correlation time of AOT molecules on the adsorbed layer is much higher. The data estimating the diffusive motion of AOT molecule show a substantially lower rate of diffusion (similar to 10(-10) cm(2)/s) in the adsorbed layers in comparison to other ones. The results show that an adsorbed layer is more rigid, whereas the outer layers undergo considerable lateral and vertical fluctuations.},
  language  = {en}
}
@article{KoethAppelhansPrietzeletal.2012,
  author    = {Koeth, Anja and Appelhans, Dietmar and Prietzel, Claudia Christina and Koetz, Joachim},
  title     = {Asymmetric gold nanoparticles synthesized in the presence of maltose-modified poly(ethyleneimine)},
  series = {Colloids and surfaces : an international journal devoted to the principles and applications of colloid and interface science ; A, Physicochemical and engineering aspects},
  volume    = {414},
  journal   = {Colloids and surfaces : an international journal devoted to the principles and applications of colloid and interface science ; A, Physicochemical and engineering aspects},
  number    = {21},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {0927-7757},
  doi       = {10.1016/j.colsurfa.2012.08.004},
  pages     = {50 -- 56},
  year      = {2012},
  abstract  = {A self-assembled tube-like network, spontaneously formed by adding maltose-modified poly(ethyleneimine) (mal-PEI5000) to mixed phospholipid vesicles, can be used as a template for the formation of gold nanoparticles. High resolution TEM indicates that the growing process leads not only to the formation of spherical gold nanoparticles with an absorption maximum at 520 nm, but also very flat triangles, hexagons, and long bent rods are formed, revealing an absorption maximum in the NIR at about 850 nm. One can conclude that nanorods, nanotriangles and nanohexagons are predominantly formed in the tubular network structure.},
  language  = {en}
}
@article{KoetzAndresKosmellaetal.2006,
  author    = {Koetz, Joachim and Andres, S. and Kosmella, Sabine and Tiersch, Brigitte},
  title     = {BaSO4 nanorods produced in polymer-modified bicontinuous microemulsions},
  issn      = {0927-6440},
  doi       = {10.1163/156855406777408629},
  year      = {2006},
  abstract  = {The influence of the water soluble polymer poly(ethylene glycol) (PEG) on structure formation in the quasiternary system sodium dodecylsulfate (SDS)/pentanol-xylene/water was checked by means of conductometry, rheology, and micro differential calorimetry. The polymer induces the formation of an isotropic phase channel between the o/w and w/o microemulsion. The transition from the normal as well as from the inverse micellar to the bicontinuous phase range can be detected by conductometry, rheology as well as micro-DSC. As a result of polymer-surfactant interactions, the spontaneous curvature of the surfactant film is changed and a sponge phase is formed. The bicontinuous phase is characterized by a moderate shear viscosity, a Newtonian flow behaviour, and the disappearence of interphasal water in the heating curve of the micro-DSC. When the polymer-modified bicontinuous phase is used as a template phase for the nanoparticle formation, spherical BaSO4 nanoparticles were formed. During the following solvent evaporation process the primarily formed spherical nanoparticles aggregate to nanorods and triangular structures due to the non-restriction of the bicontinuous template phase in longitudinal direction},
  language  = {en}
}