Many physical properties of polymers, such as glass transition, wetting, structural relaxation, mechanical properties, dynamics, and crystallization are influenced by interactions between the macromolecules and external interfaces. In this talk we will discuss the role of macromolecular architecture, and in particular the star-shaped architecture, on the structure and dynamics of the polymers close to surfaces and interfaces. We will provide evidence that the behavior of polymer at the vicinity of an interface can be tailored not by changing the monomer or the interface chemistry, but simply by changing the macromolecular architecture and in particular through changes of the molecular characteristics (number of arms and arm length) of star-shaped polymers.
In the first part of the talk we will show that star-shaped polystyrene (SPS) molecules exhibit notably different wetting properties than their linear analogues (linear polystyrene, LPS). In particularly the equilibrium contact angles of macroscopic droplets of SPS, on oxidized silicon substrates, may be as much as one order of magnitude smaller than that of LPS droplets on the same substrates.
Unlike linear chains, the wetting of SPS macromolecules is determined by the competition between their enhanced adsorption onto surfaces with increasing functionality (number of arms, f), and an opposing soft steric entopic repulsion with increasing f that limits their ability to adsorbed and closely “pack” onto surfaces. In the second part of the talk, we will show how the aforementioned competing effects in the interfacial properties of SPS are manifested on the vitrification behavior of SPS supported films. Experiments do show evidence of ordered organization of the molecules in the form of layers, in a manner identical to soft colloid particles. These results will be summarized in terms of a ‘’Diagram of States’’
Time:
10:00
Location:
Αίθουσα Σεμιναρίων 3ος όροφος Τμήματος Φυσικής
Description:
Πρόσκληση παρουσίασης Διδακτορικού
Γεώργιος Καστελλάκης
«Υπολογιστική μελέτη του ρόλου των δενδριτών στην κατανομή μνήμης σε νευρώνες και συνάψεις»
Επιβλέπουσα : Αν. Καθηγήτρια Κ. Λύκα
Συνεπιβλέπουσα: Ερευνήτρια Α, Π.Ποϊράζη
This presentation will review our recent progress on the application of ultrafast lasers for the three-dimensional biomimetic modification of materials’ surfaces for neural tissue engineering applications. We show that the artificial surfaces obtained by femtosecond laser texturing of solids comprise dual scale quasiperiodic structures at the micro- and nano- length scales that better simulate the morphology of the extracellular matrix. The ability to precisely control the structures’ geometry and pattern regularity is an important advantage for the use of the laser fabricated surfaces as models to study the dependence of growth, division and differentiation of cells on topographical cues. We focus on the control of the outgrowth of neuronal cultured cells which is of critical importance in a wide spectrum of neuro-science applications, including tissue engineering scaffolds and neural electrodes. For this purpose, laser-patterned silicon surfaces comprising arrays of micro/nano cones were employed.
It is shown that the geometrical characteristics of the structured surfaces alone could drive the directional outgrowth of neurons, glial cells as well as complex cell cultures of the peripheral nervous system. This distinct inherent property of the microstructures to direct cell outgrowth, combined with the conductance of the material, could potentially be useful for patterning neurons into artificial networks, as well as for the development of microchip-based devices that can electrically interface neuronal networks of defined directional topologies.
Time:
12:00
Location:
Teleconference room, Biology Dept. University of Crete
Description:
Πρόσκληση παρουσίασης Διδακτορικού
Έστερ Καλέφ-Εζρά
«Μιτοχονδριακή στόχευση της ανθρώπινης γλουταμικής αφυδρογονάσης: δομή σινιάλου στόχευσης, λειτουργία και εξέλιξη»
14:30-15:00 From QPCR to Digital PCR
Dominique Dewolf, Senior Field Application Specialist, Thermo Fisher Scientific
For more information, please contact your local sales representative:
Name: Litsa Stamkou
Telephone:+30 210 7795980
Em ail: litsa.stamkou@antisel.gr
Time:
12:00
Location:
main amphitheater of IMBB
Description:
It is with great pleasure that we announce the visit of Prof. Frank Sobott at IMBB on March 30-31st. Prof. Sobott is a pioneer in the emerging field of Native Mass Spectrometry, a powerful tool for structural biology. He is going to give a talk on Thursday the 31st of March in the main amphitheater of IMBB at 12.00. In the attached file you will find details about his talk and a brief CV.
In case you would like any further information or to arrange a meeting with Prof. Sobott please contact Dr. M. Aivaliotis.