报告人：Prof. Dr. Peter Müller-Buschbaum
报告时间：10月10日下午13:30
地点：18号楼218
报告题目：Thermoresponsive properties of linear- and cyclic-poly(N-isopropylacrylamide) thin films
报告人：Dr. Volker Körstgens
报告时间：10月10日下午13:30
地点：18号楼218
报告题目：X-ray scattering for soft and hybrid materials –Applications for solutions, films and fibers
报告人：Dr. Ezzeldin Metwalli
报告时间：10月10日下午13:30
地点：18号楼218
报告题目：Nanostructured soft hybrid materials at interfaces
Prof. Dr. Peter Müller-Buschbaum
Lehrstuhl für Funktionelle Materialien
Physik-Department
Technische Universität München
Peter Müller-Buschbaum is professor at Technische Universität München, heading the chair of Functional Materials in replacement of Professor Petry, since 2006. He is heading the keylab ‘TUM.solar’, which focuses on research of solar energy conversion and storage based on nanomaterials. He is heading the ‘Network for Renewable Energies’ (NRG) of the ‘Munich School of Engineering’ (MSE) and he is the German representative at the ‘European Polymer Federation’ (EPF) for polymer physics. He is elected chairman of the ‘Hamburg User Committee’ (HUC) at the synchrotron radiation laboratory DESY in Hamburg, member of the ‘European Synchrotron User Organization’ (EUSO) and associate editor of the journal “ACS Applied Materials & Interfaces”. His research focus is on polymer and hybrid nanostructures with special emphasis on advanced scattering experiments.
Talk: Thermoresponsive properties of linear- and cyclic-poly(N-isopropylacrylamide) thin films
Stimuli-responsive hydrogels are a widely studied field of polymers with a huge potential of applications such as drug-delivery systems and sensors. Among this type of hydrogels poly(N-isopropylacrylamide) (PNIPAM) is a well-known representative as a model system of a thermo-responsive polymer. The demixing transition of aqueous solutions of PNIPAM has been widely investigated in basic and applied research. It is of the lower critical solution temperature type. Because of the large volume change accompanying this phase separation, it is also denoted as a volume phase transition. It was shown by comparative studies of linear and cyclic PNIPAM that a cyclic topography of the polymer greatly influences the switching behavior. Within the scope of this study the properties of spin-coated thin films of linear and cyclic PNIPAM with well-defined molecular weights and different film thicknesses are investigated. Film swelling, when exposed to water vapor, and the switching behavior under a thermal stimulus is investigated. Due to the confinement by the substrate no uniform (3D) swelling but a 1D swelling that results in a thickness change of the films is observed by white-light interferometry and further analyzed. Moreover, the chain conformation is studied as function of film thickness using advanced scattering methods.
Nanostructured soft hybrid materials at interfaces
Ezzeldin Metwalli
Technische Universität München, Physik-Department, Lehrstuhl für Funktionelle Materialien, Garching, Germany
Soft matter science is a growing field of research, attracting equal attention from physicists, chemists, and engineers. The weak interactions between organic soft matter molecules enable the formation of nanostructured soft materials [1-4]. Furthermore, nanostructured soft mater films can be employed as templates to fabricate inorganic/organic hybrid nanomaterials. Investigations of the structure and dynamics of these systems are challenging. Scattering methods are utilized to analyze soft matter systems in a comprehensive manner. Methods such as small-angle neutron or X-ray scattering have become indispensable tools in the field of soft matter science. Two examples will be demonstrated showing how soft nanotemplates are used to guide metal atoms self-assembly into metal nanopatterns. The first example demonstrates utilization of grazing incidence small-angle X-ray scattering (GISAXS) to monitor the metal nanoparticles nucleation/growth on soft surfaces. The second example will demonstrate the ability to systematically investigate the structure of metal-polymer hybrid films from solid-polymer to polymer-air interfaces using grazing incidence small-angle neutron scattering (GISANS). The potential applications in relation to medical instrumentation and magnetic sensors are highly feasible based on the superparamagnetic behaviors of these fabricated metal-polymer hybrid films.
References:
1. [1] Yao, Y., Metwalli, E., Moulin, J. F., Su, B., Opel, M., and Müller-Buschbaum, P.; Self-Assembly of Diblock Copolymer-Maghemite Nanoparticle Hybrid Thin Films; ACS Appl Mater Inter, 6, 18152 (2014)
2. [2] Yao, Y., Metwalli, E., Opel, M., Haese, M., Moulin, J. F., Rodewald, K., Rieger, B., and Müller-Buschbaum, P.; Lamellar Diblock Copolymer Films with Embedded Maghemite Nanoparticles; Adv. Mater. Interfaces, Adv. Mater. Interfaces 3, 1500712 (2016)
3. [3] Metwalli, E., Krisch, I., Markovits, I., Rawolle, M., Ruderer, M. A., Guo, S., Wyrzgol, S., Jentys, A., Perlich, J., Lercher, J. A., and Müller-Buschbaum, P.; Polymer-Coated PtCo Nanoparticles Deposited on Diblock Copolymer Templates: Chemical Selectivity versus Topographical Effects; ChemPhysChem, 15, 2236 (2014)
4. [4] Metwalli, E., Moulin, J. F., Rauscher, M., Kaune, G., Ruderer, M. A., Van Burck, U., Haese-Seiller, M., Kampmann, R., and Müller-Buschbaum, P.; Structural Investigation of Thin Diblock Copolymer Films Using Time-of-Flight Grazing-Incidence Small-Angle Neutron Scattering; J. Appl. Crystallogr, 44, 84 (2011)
Dr. Ezzeldin Metwalli
Graduation in Chemistry and PhD in Chemistry at Ain Shams University, in Cairo, were followed by a postdoctoral work in 1999 at Materials science and engineering department at University of Missouri-Rolla, USA, in 2000 as a postdoctoral fellow at material science and engineering at Penna State University, USA. In 2002 was appointed as a R&D senior scientist at Schott AG, Mainz Germany, in 2005 as a postdoc fellow at chair of functional materials, physics departments, TU Munich, Germany. Since 2013, I have appointed as assistant professor (Habilitand) at physics department, TU Munich, Germany.
X-ray scattering for soft and hybrid materials –
Applications for solutions, films and fibers
Abstract: An overview of the broad field of x-ray scattering methods for the structural investigation of soft matter and hybrid materials is given. After a brief introduction of the basic principles it will be discussed how the morphology of soft materials in such different forms as solutions, thin films and textile fibers can be determined with x-ray scattering. As an example an experimental microfluidic technique will be presented which allows for versatile structural investigations at the solid-liquid interface with high time resolution. In our approach reflection geometry using GISAXS (grazing incidence small angle x-ray scattering) is combined with a special designed microfluidic cell. The in-situ technique was successfully applied in the investigation of the swelling of thin films, attachment processes as in the layer formation of nanoparticles, structural changes in composite films, as well as in the study of nanoparticle growth processes.
Authors’ notes:
Dr. Volker Körstgens works as a scientist at the chair
for functional materials at the physics department of
Technische Universität München, Germany.
Main fields of his research are hybrid materials for
energy applications and the development of
characterization methods for these nanostructured
materials.
e-mail: volker.koerstgens@ph.tum.de
