 Please Fill out this form in English and upload all PDF format for the files.
If you have any companions, please combine all tickets in to one PDF file and upload. You should do it for Visas too.
|
|
Name : |
Mohammad |
|
Surname : |
Raoufi |
|
From : |
Wednesday, July 17, 2019 |
|
To : |
Sunday, December 22, 2019 |
|
Position : |
Assistant professor |
|
subject : |
|
Research and analysis finishing our join project writing the proposal |
|
|
Venue : |
University of Siegen-Maxplanck for inteligent system |
|
Sabbatical Leave Period : |
6 months |
|
Country : |
Germany |
|
1.Brief summary of Leave : |
I join my former supervisors to continue some of join program and writhing the proposal for DFG The modification of cylindrical anodic aluminum oxide (AAO) nanopores by alternating layer by layer (LBL) deposition of poly(sodium-4-styrene sulfonate) (PSS) and poly(allylamine hydrochloride) (PAH) was studied in situ by Reflectometric Interference Spectroscopy (RIfS). In particular, the kinetics of polyelectrolyte deposition inside the 37 ± 3 nm diameter and 3.7 ± 0.2 µm long pores was unraveled and potential differences in LBL multilayer growth compared to flat silicon substrates and the effect of different ionic strengths and different types of ions were investigated. RIfS measures the effective optical thicknesses, which is for constant pore length proportional to the effective refractive index of the AAO sample, from which in turn the deposited mass of polymer or the corresponding layer thickness can be estimated. Compared to the multilayer growth by LBL deposition on flat amino-silane primed silicon wafers, which was assessed by spectroscopic ellipsometry, the thickness increment per deposited bilayer as well as the dependence of this increment on ionic strength (0.01 to 0.15) and counter ion type (Na+ vs. Ca2+) inside the amino-silane primed nanopores was for the first bilayers to within the experimental error identical. For thicker multilayers, the pore diameter became smaller, which led to reduced thickness increments and eventually virtually completely filled pores. The observed kinetics is consistent with a mass transport limited adsorption of the polyelectrolyte to the charged surface according to a Langmuir isotherm with negligible desorption rate. In addition to fundamental insight into the build-up of polyelectrolyte multilayers inside AAO nanopores, our results highlight the sensitivity of RIfS and its use as analytical tool for probing processes inside nanopores and for the development of biosensors |
|
2.List the objectives of your sabbatical leave as listed in your proposal and indicate how completely they were met : |
1- finish some of our join project 2- write the proposal for DFG 3- doing analysis of some research project was done in Iranwith their facilities The modification of cylindrical anodic aluminum oxide (AAO) nanopores by alternating layer by layer (LBL) deposition of poly(sodium-4-styrene sulfonate) (PSS) and poly(allylamine hydrochloride) (PAH) was studied in situ by Reflectometric Interference Spectroscopy (RIfS). In particular, the kinetics of polyelectrolyte deposition inside the 37 ± 3 nm diameter and 3.7 ± 0.2 µm long pores was unraveled and potential differences in LBL multilayer growth compared to flat silicon substrates and the effect of different ionic strengths and different types of ions were investigated. RIfS measures the effective optical thicknesses, which is for constant pore length proportional to the effective refractive index of the AAO sample, from which in turn the deposited mass of polymer or the corresponding layer thickness can be estimated. Compared to the multilayer growth by LBL deposition on flat amino-silane primed silicon wafers, which was assessed by spectroscopic ellipsometry, the thickness increment per deposited bilayer as well as the dependence of this increment on ionic strength (0.01 to 0.15) and counter ion type (Na+ vs. Ca2+) inside the amino-silane primed nanopores was for the first bilayers to within the experimental error identical. For thicker multilayers, the pore diameter became smaller, which led to reduced thickness increments and eventually virtually completely filled pores. The observed kinetics is consistent with a mass transport limited adsorption of the polyelectrolyte to the charged surface according to a Langmuir isotherm with negligible desorption rate. In addition to fundamental insight into the build-up of polyelectrolyte multilayers inside AAO nanopores, our results highlight the sensitivity of RIfS and its use as analytical tool for probing processes inside nanopores and for the development of biosensors |
|
3.Acheivements(Publications,research,et.al.) : |
Results: 3 journal publication and one proposal for DFG that was not successful |
|
4.Assessment of Value of Sabbatical leave(benefits,faculty development,future professional activities,...) : |
Results: 3 journal publication and one proposal for DFG that was not successful Plan was to be there for join program to write the big proposal for DFG unfortunately we are rejected for this proposal in finial steps. Still we are working on this proposal and hopefully we can get acceptance after Covid period The modification of cylindrical anodic aluminum oxide (AAO) nanopores by alternating layer by layer (LBL) deposition of poly(sodium-4-styrene sulfonate) (PSS) and poly(allylamine hydrochloride) (PAH) was studied in situ by Reflectometric Interference Spectroscopy (RIfS). In particular, the kinetics of polyelectrolyte deposition inside the 37 ± 3 nm diameter and 3.7 ± 0.2 µm long pores was unraveled and potential differences in LBL multilayer growth compared to flat silicon substrates and the effect of different ionic strengths and different types of ions were investigated. RIfS measures the effective optical thicknesses, which is for constant pore length proportional to the effective refractive index of the AAO sample, from which in turn the deposited mass of polymer or the corresponding layer thickness can be estimated. Compared to the multilayer growth by LBL deposition on flat amino-silane primed silicon wafers, which was assessed by spectroscopic ellipsometry, the thickness increment per deposited bilayer as well as the dependence of this increment on ionic strength (0.01 to 0.15) and counter ion type (Na+ vs. Ca2+) inside the amino-silane primed nanopores was for the first bilayers to within the experimental error identical. For thicker multilayers, the pore diameter became smaller, which led to reduced thickness increments and eventually virtually completely filled pores. The observed kinetics is consistent with a mass transport limited adsorption of the polyelectrolyte to the charged surface according to a Langmuir isotherm with negligible desorption rate. In addition to fundamental insight into the build-up of polyelectrolyte multilayers inside AAO nanopores, our results highlight the sensitivity of RIfS and its use as analytical tool for probing processes inside nanopores and for the development of biosensors |
|
Additional material may be attached in response to the above summary : |
http://gsia.tums.ac.ir/images/UserFiles/64908/Forms/280/In Situ Study of Layer-by-Layer Polyelectrolyte Deposition in Nanopores of Anodic Aluminum Oxide by Reflectometric Interference Spectroscopy_2.pdf |
|
Department Head/Research Center Chair : |
University Siegen- Department of Biochemistry- Prof Holger Schoenherr Max Planck For intelligent system Stuttgart, Prof Joachim Spatz |
|
Any Related to Report File : |
http://gsia.tums.ac.ir/images/UserFiles/64908/Forms/280/Poly_diethylene_glycol_methylether_methacrylate__Brush-Functionalized_Anodic_Alumina_Nanopores_Curvature-Dependent_Polymerization_Kinetics_and_Nanopore_Filling.pdf |