@article{RajuLiebigKlemkeetal.2018,
  author    = {Raju, Rajarshi Roy and Liebig, Ferenc and Klemke, Bastian and Koetz, Joachim},
  title     = {pH-responsive magnetic Pickering Janus emulsions},
  series = {Colloid and polymer science : official journal of the Kolloid-Gesellschaft},
  volume    = {296},
  journal   = {Colloid and polymer science : official journal of the Kolloid-Gesellschaft},
  number    = {6},
  publisher = {Springer},
  address   = {New York},
  issn      = {0303-402X},
  doi       = {10.1007/s00396-018-4321-z},
  pages     = {1039 -- 1046},
  year      = {2018},
  abstract  = {We report ultrasonically generated pH-responsive Pickering Janus emulsions of olive oil and silicone oil with controllable droplet size and engulfment. Chitosan was used as a pH-responsive emulsifier. The increase of pH from 2 to 6 leads to a transition from completely engulfed double emulsion droplets to dumbbell-shaped Janus droplets accompanied by a significant decrease of droplet diameter and a more homogeneous size distribution. The results can be elucidated by the conformational change of chitosan from a more extended form at pH 2 to a more flexible form at pH 4-5. Magnetic responsiveness to the emulsion was attributed by dispersing superparamagnetic nanoparticles (Fe3O4 with diameter of 13 +/- 2 nm) in the olive oil phase before preparing the Janus emulsion. Incorporation of magnetic nanoparticles leads to superior emulsion stability, drastically reduced droplet diameters, and opened the way to control movement and orientation of the Janus droplets according to an external magnetic field.},
  language  = {en}
}
@article{KosmellaKlemkeHaeusleretal.2019,
  author    = {Kosmella, Sabine and Klemke, Bastian and H{\"a}usler, Ines and Koetz, Joachim},
  title     = {From gel-like Pickering emulsions to highly ordered superparamagnetic magnetite aggregates with embedded gold nanoparticles},
  series = {Colloids and surfaces : an international journal devoted to the principles and applications of colloid and interface science ; A, Physicochemical and engineering aspects},
  volume    = {570},
  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 Science},
  address   = {Amsterdam},
  issn      = {0927-7757},
  doi       = {10.1016/j.colsurfa.2019.03.017},
  pages     = {331 -- 338},
  year      = {2019},
  abstract  = {Pickering emulsions with two types of nanoparticles, i.e., superparamagnetic magnetite nanoparticles dispersed in n-hexane and gold nanoparticles dispersed in water, were formed by rigorous mixing in presence of surface active polymeric surfactants. Monodisperse magnetite nanoparticles with a mean particle size of 4 nm were obtained by a microwave-assisted synthesis in n-hexane in presence of oleic acid, and gold nanoparticles were produced in aqueous solution in presence of the hyperbranched poly(ethyleneimine) (PEI) or sodium citrate as reducing and stabilizing agent. After mixing the prepared nanoparticle dispersions in presence of the Pluronics an intermediate gel-like phase is formed. The Pickering emulsion droplets in the intermediate phase are stabilized by both types of nanoparticles, as to be seen by cryo-SEM micrographs. After separating, solvent evaporation and redispersion in water highly ordered Pluronic-stabilized superparamagnetic magnetite nanoparticle aggregates with embedded gold nanoparticles can be obtained.},
  language  = {en}
}
@article{SchulzeAppelhansTierschetal.2014,
  author    = {Schulze, Nicole and Appelhans, D. and Tiersch, Brigitte and Koetz, Joachim},
  title     = {Morphological transformation of vesicles into tubular structures by adding polyampholytes or dendritic glycopolymers},
  series = {Colloids and surfaces : an international journal devoted to the principles and applications of colloid and interface science ; A, Physicochemical and engineering aspects},
  volume    = {457},
  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.2014.06.007},
  pages     = {326 -- 332},
  year      = {2014},
  abstract  = {For the first time tubulating properties of spherical dendritic glycopolymers and linear alternating polyampholytes against non-uniform negatively charged giant vesicles are proven by light microscopy and cryo-scanning electron microscopy study. Real time observation of the morphological transformation from giant vesicles to tubular structures, simulating morphogenesis in living cells, is given by using the cationic and H-bond active dendritic glycopolymer accompanied by reducing the size of the giant vesicles and the evidence of vesicle-vesicle interaction which was only postulated in a previous study. Similar morphogenesis of non-uniform giant vesicles into tubular network structure can be observed by using a polyampholyte in the stretched conformation at pH 9. Pearl necklace and tubular network structure formation are also observed by applying anionic vesicles of significant smaller dimensions with average size dimensions of 35 nm, after adding the polyampholyte at pH 9. However, the fitting accuracy between the functional groups along the backbone chain of the polyampholyte on one side and the vesicle surface on the other side is of high importance for the transformation process by using polyampholytes. The resulting tubular and network structures offer new fields of application as microfluidic transport channels or template phases for the shape controlled formation of nanoparticles. (C) 2014 Elsevier B.V. All rights reserved.},
  language  = {en}
}
@article{SchulzeTierschZenkeetal.2013,
  author    = {Schulze, Nicole and Tiersch, B. and Zenke, I. and Koetz, Joachim},
  title     = {Polyampholyte-tuned lyotrop lamellar liquid crystalline systems},
  series = {COLLOID AND POLYMER SCIENCE},
  volume    = {291},
  journal   = {COLLOID AND POLYMER SCIENCE},
  number    = {11},
  publisher = {SPRINGER},
  address   = {NEW YORK},
  issn      = {0303-402X},
  doi       = {10.1007/s00396-013-2999-5},
  pages     = {2551 -- 2559},
  year      = {2013},
  abstract  = {The influence of a polyampholyte, i.e., poly(N,N\’-diallyl-N,N\’-dimethyl-altmaleamic carboxylate) (PalH), on the lamellar liquid crystalline (LC) system sodium dodecyl sulfate (SDS)/decanol/water was investigated by means of microdifferential scanning calorimetry, small-angle X-ray diffraction (SAXS), and cryo-scanning electron microscopy. After incorporating PalH into the lamellar liquid crystalline system, SAXS measurements show that three different LC phases exist: i.e., a swelling, slightly swelling, and non-swelling one. At pH 4, the positively charged polymer with an extended conformation can directly adsorb at the anionic head groups of the surfactant and more compact vesicles are formed at room temperature. At pH 9, the electrostatic interactions between the polyampholyte (in a more coiled conformation) and the sulfate head groups of the SDS are leveled off and incompact vesicles are formed at room temperature. That means in presence of the polyampholyte the morphology of the LC phase, i.e., the supramolecular vesicle structure, can be tuned by varying the pH and/or the temperature.},
  language  = {en}
}