Search results for "Soft matter"
showing 4 items of 54 documents
Can one detach a fully adsorbed flexible polymer chain by an ultra-small external force?
2013
Full adsorption of flexible chains onto typical solid substrates occurs at a surface interaction energy of (5–10) kBT. The corresponding detachment force is in the range 10–50 pN. In contrast to “bare” solid substrates common to non-living materials, surfaces coated with brush-like polymer layers are very common in biological soft matter. We employ a simple mean-field approach to describe the effects of weak attraction between a floating long macromolecule and the brush. We show that even for a moderately thick brush a very small effective attraction is enough to produce complete binding of the long chain. The detachment force scales as , where W is the brush thickness. Hence the force coul…
Transient Hydrogels Mediated by Redox-Switchable Supramolecular Polymerization
2017
Spatial and temporal control in multi-stimuli-responsive materials are critical properties to advance and optimize functional soft matter in order to mimic key features of living systems. In this contribution, I will discuss our methodology in developing non-equilibrium states in supramolecular materials. We have expanded our concept of charge regulated s–sheet self-assembly of alternating hydrophilic and hydrophobic amino acids in order to introduce redox-switchable properties. An interplay of pH- and oxidation-stimuli, promoted by the production of reactive oxygen species (ROS) thus leads to transient supramolecular polymerizations of methionine containing amphiphiles, with tuneable lifet…
Liposomes modified by mono- and bis-phthalocyanines: A comprehensive EPR study.
2016
The impact of selected metallophthalocyanines, featuring diverse molecular structure, upon the fluidity of liposome membranes was studied using the spin label EPR technique. The “mono”-type MPc’s (M = Zn, Sn; Pc = C32H16N8 is the phthalocyanine ligand) and sandwich LnPc2 complexes (Ln = Nd, Sm, Gd) were explored. Liposomes were obtained in a sonication process, from egg yolk lecithin (EYL) in water. TEMPO and 16-DOXYL spin labels were used to monitor the peripheral and central part of the lipid double layer, respectively, which allowed to localize the phthalocyanine additive within the bilayer, as well as to perform independent measurements of changes in fluidity upon addition thereof. All …
78th Scientific Conference. Section: Magnetic Soft Matter: Book of Abstracts
2020
February 14th, 2020; University of Latvia. Faculty of Physics, Mathematics and Optometry; House of Science, Jelgavas 3, Riga, Latvia