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SUMMARY:Basic aspects of neutron science and soft matter/ infrastructures 
 at the Institute Laue Langevin (ILL) - Polymer compatibility on mixed brus
 hes probed by high pressure GISANS (HPGISANS) and reflectivity
DTSTART:20260514T110000Z
DTEND:20260514T120000Z
DTSTAMP:20260611T204700Z
UID:indico-event-1598@indico.ifj.edu.pl
DESCRIPTION:Speakers: Apostolos Vagias (Institut Max von Laue-Paul Langevi
 n ILL\, Grenoble\, France)\n\n\n \nIn the first part of my talk\, I will 
 cover basic aspects about neutron scattering for soft matter systems. I wi
 ll then present an overview of the Large Scale Structures Group at the Ins
 titute Laue - Langevin (ILL). In the second part\, I will focus on my own 
 research background concerning supported soft matter using neutron methods
  under ambient and extreme conditions (high hydrostatic pressure and tempe
 rature). Background: The elucidation of material nanostructure under eleva
 ted pressures is quite relevant for devices used in deep sea research\, in
 cluding tactile sensors and soft robotics [1]. To accommodate resistance t
 o harsh underwater environments\, multicomponent systems need to be utiliz
 ed with orthogonal properties. Technical challenges had so far hampered th
 e investigation of thin film nanostructures of varying compositional compl
 exity under elevated hydrostatic pressures. Methods: By utilizing a custom
 -made pressure cell [2] and performing Grazing Incidence Small Angle Neutr
 on Scattering under pressure (HP - GISANS) at D22 and neutron reflectometr
 y (NR) at FIGARO instruments of the ILL [3\,4]\, I compare effects of pres
 sure and temperature at the solid-liquid interface between two homopolymer
  mixed brushes in thin (< 100 nm) film using D2O solvent: A weakly incompa
 tible (poly(methyl methacrylate) / poly(2-(dimethylamino)ethyl methacrylat
 e)) (PMMA /PDMAEMA) and strongly incompatible ((poly((2\,2\,3\,3\,4\,4\,5\
 ,5-octafluoro)pentyl methacrylate))/ poly(2-(dimethylamino)ethyl methacryl
 ate) ) (POFPMA/PDMAEMA) mixed brush. Results: Distinct pressure-dependent 
 response in lateral (HP - GISANS) and transversal (specular NR) nanostruct
 ure is recorded depending on the chemical compatibility between the polyme
 rs. GISANS simulations indicate buried hydrophobic dimple-like patches wit
 hin a PDMAEMA-based swollen matrix. Specular ToF-NR suggests that temperat
 ure effects are counteracted by pressure. Off-specular NR reveals large (>
 100 nm) lateral domains associated to the hydrophilic PDMAEMA compound\, b
 eing both pressuredependent and polymer-compatibility dependent. Conclusio
 n: Length scale of phase separation strongly depends on the compositional 
 variation in the flat mixed brushes. Also\, non-idealities of mixing are p
 olymer-compatibility dependent as evidenced by enhanced D2O retention with
 in the brush by the more strongly incompatible POFPMA/PDMAEMA.\n \n[1] Li
  G.\, et al.\, Nature Communications (2023) 14\, 7097 \; [2] Kreuzer\, M.
 \, et al.\, Rev. Sci. Instr. (2011) 82\, 023902 \; [3] Vagias A. et al.\,
  J. Appl. Cryst. (2024) 57\, 1978-198 \; [4] Vagias A. et al.\, (submitte
 d) \n\nhttps://indico.ifj.edu.pl/event/1598/
URL:https://indico.ifj.edu.pl/event/1598/
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