@article{HenningLiebigPrietzeletal.2020, author = {Henning, Ricky and Liebig, Ferenc and Prietzel, Claudia Christina and Klemke, Bastian and Koetz, Joachim}, title = {Gold nanotriangles with magnetite satellites}, series = {Colloids and surfaces : an international journal devoted to the principles and applications of colloid and interface science ; A, Physicochemical and engineering aspects}, volume = {600}, 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.2020.124913}, pages = {7}, year = {2020}, abstract = {This work describes the synthesis of hybrid particles of gold nanotriangles (AuNTs) with magnetite nanoparticles (MNPs) by using 1-mercaptopropyl-3-trimethoxysilan (MPTMS) and L-cysteine as linker molecules. Due to the combination of superparamagnetic properties of MNPs with optical properties of the AuNTs, nanoplatelet-satellite hybrid nanostructures with combined features become available. By using MPTMS with silan groups as linker molecule a magnetic "cloud" with embedded AuNTs can be separated. In presence of L-cysteine as linker molecule at pH > pH(iso) a more unordered aggregate structure of MNPs is obtained due to the dimerization of the L-cysteine. At pH < pH(iso) water soluble positively charged AuNTs with satellite MNPs can be synthesized. The time-dependent loading with MNP satellites under release of the extinction and magnetization offer a hybrid material, which is of special relevance for biomedical applications and plasmonic catalysis.}, language = {en} } @misc{HornConradSeipLiebigetal.2023, author = {Horn-Conrad, Antje and Seip, Juliane and Liebig, Ferenc and Engel, Silke and Schuster, Stefanie and Jung, Karina and Aust, Sarah-Madeleine and Kampe, Heike and Lentz, Christine and Mikulla, Stefanie and Zimmermann, Matthias and Agrofylax, Luisa and Scholz, Jana and Schmidt, Debby}, title = {Portal Transfer}, number = {2023}, issn = {2747-6898}, doi = {10.25932/publishup-61365}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-613650}, pages = {78}, year = {2023}, abstract = {Liebe Leserinnen und Leser, kein Nachrichtentag vergeht, an dem nicht die Expertise aus der Wissenschaft gefragt ist: Ob zum russischen Angriffskrieg in der Ukraine, zur UNKlimakonferenz in {\"A}gypten, zur Flutkatastrophe in Pakistan, zum D{\"u}rresommer, zur Energiekrise, selbst zur umstrittenen Fußballweltmeisterschaft in Katar standen und stehen Expertinnen und Experten in den Medien Rede und Antwort. Auch aus der Universit{\"a}t Potsdam. Wir haben sie gefragt, wie sie damit umgehen, wie es ihnen gelingt, aus der laufenden Forschung heraus aktuelle Probleme zu bewerten. Und was davon bleibt, wenn das {\"o}ffentliche Interesse abebbt. F{\"u}r die Potsdamer Politik- und Verwaltungswissenschaftlerin Sabine Kuhlmann besteht die Kunst darin, „außerhalb der Krise Ideen und L{\"o}sungsans{\"a}tze zu verstetigen und sie tats{\"a}chlich in die Praxis umzusetzen". In unserem Alumni- und Transfermagazin berichten wir davon, was und wie die Universit{\"a}t Potsdam dazu beitr{\"a}gt. Wir erz{\"a}hlen, wie Erfindungen zu Innovationen in der Wirtschaft werden und sich Start-ups auf den Weg machen, ihr Produkt selbst zu vermarkten. Das Spektrum reicht von Meeresfr{\"u}chten auf Pflanzenbasis bis zu einer App, mit der sich Fr{\"u}hformen der Demenz erkennen lassen. Neben neuen Technologien kommt es aber vor allem darauf an, das an der Universit{\"a}t erzeugte Wissen in die Praxis zu transferieren. Deshalb stellen wir ein Programm zur Bek{\"a}mpfung von Hassrede in der Schule vor oder auch eine Klettertherapie zur Behandlung von Skoliose. Und wir zeigen, wie eine Studie zur sportlichen Leistungskraft von Kindern helfen kann, den Sportunterricht zu verbessern. Den gr{\"o}ßten Teil des an der Universit{\"a}t produzierten Wissens tragen die Studierenden in die Welt, wenn sie nach ihrem Abschluss als Musiklehrerin in einer Schule arbeiten oder als Software-Ingenieur im eigenen Unternehmen, als Geologin nach Seltenen Erden sch{\"u}rfen, als {\"O}kologe ausgelaugte B{\"o}den wieder fruchtbar machen oder als Politikerin ein Ministerium leiten. Sie alle kommen in diesem Magazin zu Wort. Oder in unserem neuen Podcast „Listen.UP", in dem Studierende, Forschende und Alumni von ihren Transferprojekten erz{\"a}hlen. Von der Gr{\"u}nderin Ulrike B{\"o}ttcher erf{\"a}hrt man dort zum Beispiel, wie sie mit Schnallen, {\"O}sen und Kn{\"o}pfen aus Bio- Materialien die Modeindustrie in diesem Bereich nachhaltig ver{\"a}ndern will. Nachzulesen ist das auch in diesem Heft. Immer dort, wo das „Listen. UP"-Logo erscheint, lohnt es, zus{\"a}tzlich in den Podcast hineinzuh{\"o}ren.}, language = {de} } @article{KarpitschkaLiebigRiegler2017, author = {Karpitschka, Stefan and Liebig, Ferenc and Riegler, Hans}, title = {Marangoni Contraction of Evaporating Sessile Droplets of Binary Mixtures}, series = {Langmuir}, volume = {33}, journal = {Langmuir}, publisher = {American Chemical Society}, address = {Washington}, issn = {0743-7463}, doi = {10.1021/acs.langmuir.7b00740}, pages = {4682 -- 4687}, year = {2017}, abstract = {The Marangoni contraction of sessile drops of a binary mixture of a volatile and a nonvolatile liquid has been investigated experimentally and theoretically. The origin of the contraction is the locally inhomogeneous evaporation rate of sessile drops. This leads to surface tension gradients and thus to a Marangoni flow. Simulations show that the interplay of Marangoni flow, capillary flow, diffusive transport, and evaporative losses can establish a quasistationary drop profile with an apparent nonzero contact angle even if both liquid components individually wet the substrate completely. Experiments with different solvents, initial mass fractions, and gaseous environments reveal a previously unknown universal power-law relation between the apparent contact angle and the relative undersaturation of the ambient atmosphere: theta(app) similar to (RHeq - RH)(1/3). This experimentally observed power law is in quantitative agreement with simulation results. The exponent can also be inferred from a scaling analysis of the hydrodynamic-evaporative evolution equations of a binary mixture of liquids with different volatilities.}, language = {en} } @phdthesis{Liebig2018, author = {Liebig, Ferenc}, title = {Synthesis and characterization of superstructures based on gold nanotriangles}, school = {Universit{\"a}t Potsdam}, pages = {136}, year = {2018}, 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} } @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{LiebigMorenoThuenemannetal.2018, author = {Liebig, Ferenc and Moreno, Silvia and Thuenemann, Andreas F. and Temme, Achim and Appelhans, Dietmar and Koetz, Joachim}, title = {Toxicological investigations of "naked" and polymer-entrapped AOT-based gold nanotriangles}, series = {Colloids and surfaces : an international journal devoted to fundamental and applied research on colloid and interfacial phenomena in relation to systems of biological origin ; B, Biointerfaces}, volume = {167}, journal = {Colloids and surfaces : an international journal devoted to fundamental and applied research on colloid and interfacial phenomena in relation to systems of biological origin ; B, Biointerfaces}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0927-7765}, doi = {10.1016/j.colsurfb.2018.04.059}, pages = {560 -- 567}, year = {2018}, abstract = {Negatively charged ultrathin gold nanotriangles (AuNTs) were synthesized in a vesicular dioctyl sodium sulfosuccinate (AOT)/phospholipid-based template phase. These "naked" AuNTs with localized surface plasmon resonances in the NIR region at about 1300 nm and special photothermal properties are of particular interest for imaging and hyperthermia of cancerous tissues. For these kinds of applications the toxicity and the cellular uptake of the AuNTs is of outstanding importance. Therefore, this study focuses on the toxicity of "naked" AOT-stabilized AuNTs compared to polymer-coated AuNTs. Polymeric coating consisted of non-modified hyperbranched poly(ethyleneimine) (PEI), maltose-modified poly(ethyleneimine) (PEI-Mal) and heparin. The toxicological experiments were carried out with two different cell lines (embryonic kidney carcinoma cell line HEK293T and NK-cell leukemia cell line YTS). This study revealed that the heparin-coating of AuNTs improved biocompatibility by a factor of 50 when compared to naked AuNTs. Of note, the highest nontoxic concentration of the AuNTs coated with PEI and PEI-Mal is drastically decreased. Overall, this is mainly triggered by the different surface charges of polymeric coatings. Therefore, AuNTs coated with heparin were selected to carry out uptake studies. Their promising high biocompatibility and cellular uptake may open future studies in the field of biomedical applications. (C) 2018 Elsevier B.V. All rights reserved.}, language = {en} } @misc{LiebigSarhanBargheeretal.2020, author = {Liebig, Ferenc and Sarhan, Radwan Mohamed and Bargheer, Matias and Schmitt, Clemens Nikolaus Zeno and Poghosyan, Armen H. and Shahinyanf, Aram A. and Koetz, Joachim}, title = {Spiked gold nanotriangles}, series = {Postprints der Universit{\"a}t Potsdam : Mathematisch Naturwissenschaftliche Reihe}, journal = {Postprints der Universit{\"a}t Potsdam : Mathematisch Naturwissenschaftliche Reihe}, number = {829}, issn = {1866-8372}, doi = {10.25932/publishup-44556}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-445568}, pages = {11}, year = {2020}, abstract = {We show the formation of metallic spikes on the surface of gold nanotriangles (AuNTs) by using the same reduction process which has been used for the synthesis of gold nanostars. We confirm that silver nitrate operates as a shape-directing agent in combination with ascorbic acid as the reducing agent and investigate the mechanism by dissecting the contribution of each component, i.e., anionic surfactant dioctyl sodium sulfosuccinate (AOT), ascorbic acid (AA), and AgNO3. Molecular dynamics (MD) simulations show that AA attaches to the AOT bilayer of nanotriangles, and covers the surface of gold clusters, which is of special relevance for the spike formation process at the AuNT surface. The surface modification goes hand in hand with a change of the optical properties. The increased thickness of the triangles and a sizeable fraction of silver atoms covering the spikes lead to a blue-shift of the intense near infrared absorption of the AuNTs. The sponge-like spiky surface increases both the surface enhanced Raman scattering (SERS) cross section of the particles and the photo-catalytic activity in comparison with the unmodified triangles, which is exemplified by the plasmon-driven dimerization of 4-nitrothiophenol (4-NTP) to 4,4'-dimercaptoazobenzene (DMAB).}, language = {en} } @article{LiebigSarhanBargheeretal.2020, author = {Liebig, Ferenc and Sarhan, Radwan Mohamed and Bargheer, Matias and Schmitt, Clemens Nikolaus Zeno and Poghosyan, Armen H. and Shahinyanf, Aram A. and Koetz, Joachim}, title = {Spiked gold nanotriangles}, series = {RSC Advances}, volume = {10}, journal = {RSC Advances}, number = {14}, publisher = {RSC Publishing}, address = {London}, issn = {2046-2069}, doi = {10.1039/d0ra00729c}, pages = {8152 -- 8160}, year = {2020}, abstract = {We show the formation of metallic spikes on the surface of gold nanotriangles (AuNTs) by using the same reduction process which has been used for the synthesis of gold nanostars. We confirm that silver nitrate operates as a shape-directing agent in combination with ascorbic acid as the reducing agent and investigate the mechanism by dissecting the contribution of each component, i.e., anionic surfactant dioctyl sodium sulfosuccinate (AOT), ascorbic acid (AA), and AgNO3. Molecular dynamics (MD) simulations show that AA attaches to the AOT bilayer of nanotriangles, and covers the surface of gold clusters, which is of special relevance for the spike formation process at the AuNT surface. The surface modification goes hand in hand with a change of the optical properties. The increased thickness of the triangles and a sizeable fraction of silver atoms covering the spikes lead to a blue-shift of the intense near infrared absorption of the AuNTs. The sponge-like spiky surface increases both the surface enhanced Raman scattering (SERS) cross section of the particles and the photo-catalytic activity in comparison with the unmodified triangles, which is exemplified by the plasmon-driven dimerization of 4-nitrothiophenol (4-NTP) to 4,4'-dimercaptoazobenzene (DMAB).}, language = {en} }