Effect of C60 filling on structure and properties of composite films based on polystyrene

Both polystyrene films and polystyrene films filled with fullerenes (C60) were fabricated by the solution cast method. Mechanism of fullerene-polystyrene interaction, the structural characteristics of films, and their antimicrobial activity were researched. We found that the polystyrene/fullerene composite films manifest bacteriostatic and fungistatic effect. Keywords: Polystyrene/fullerene composites, X-ray diffraction, IR spectroscopy, Antimicrobial activit

Effect of the bentonite filler on structure and properties of composites based on hydroxyethyl cellulose

Granulometric test and morphological analysis of the bentonite particles were performed using laser diffraction and low-temperature nitrogen adsorption–desorption techniques. Bentonite particles were immobilized into the hydroxyethyl cellulose matrix by mechanical dispersion, and composite films were obtained. The effect of concentration of the filling agent on structure and tensile properties of composites was revealed. Data on the nature of interaction between hydroxyethyl cellulose and bentonite after the modification of polymer were obtained by IR spectroscopy. It was found that the hydroxyethyl cellulose/bentonite composite films showed an antimicrobial effect against Escherichia coli and Staphylococcus aureus bacteria, as well against fungi association. Keywords: Hydroxyethyl cellulose/bentonite composites, X-ray diffraction, IR spectroscopy, Tensile properties, Antimicrobial activit

Enhancing the Thermal Stability of Ionogels: Synthesis and Properties of Triple Ionic Liquid/Halloysite/MCC Ionogels

In this study, an ionic liquid (IL), 1-butyl-3-methylimidazolium acetate, was used to prepare ionogels with microcrystalline cellulose (MCC) and halloysite (Hal). SEM, XRD, TG, DSC, FTIR spectroscopy, conductometry and mechanical tests were used to study the morphology, structure, thermal behaviour and electrophysical and mechanical characteristics of synthesised ionogels. XRD analysis showed a slight decrease in the interlayer space of halloysite in ionogels containing MCC, which may have been associated with the removal of residual water molecules resulting from hydrophilic IL anions and polymer macromolecules. A change in conductivity and glass-transition temperature of the ionic liquid was revealed due to intercalation into halloysite (a confinement effect) and modification with cellulose. For triple IL/Hal/MCC ionogels, the characteristic thermal degradation temperatures were higher than the corresponding values for IL/Hal composites. This indicates that the synthesised IL/Hal/MCC ionogels are characterised by a greater thermal stability than those of IL/Hal systems

Heterogeneous Hydration of p53/MDM2 Complex

[Image: see text] Water-mediated interactions play critical roles in biomolecular recognition processes. Explicit solvent molecular dynamics (MD) simulations and the variational implicit-solvent model (VISM) are used to study those hydration properties during binding for the biologically important p53/MDM2 complex. Unlike simple model solutes, in such a realistic and heterogeneous solute–solvent system with both geometrical and chemical complexity, the local water distribution sensitively depends on nearby amino acid properties and the geometric shape of the protein. We show that the VISM can accurately describe the locations of high and low density solvation shells identified by the MD simulations and can explain them by a local coupling balance of solvent–solute interaction potentials and curvature. In particular, capillary transitions between local dry and wet hydration states in the binding pocket are captured for interdomain distance between 4 to 6 Å, right at the onset of binding. The underlying physical connection between geometry and polarity is illustrated and quantified. Our study offers a microscopic and physical insight into the heterogeneous hydration behavior of the biologically highly relevant p53/MDM2 system and demonstrates the fundamental importance of hydrophobic effects for biological binding processes. We hope our study can help to establish new design rules for drugs and medical substances