The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
We report the synthesis and hydrogelation of star-shaped poly(l-lysine) modified with indole or phenyl group (s-PLL-g-Indo or s-PLL-g-Phenyl). The star-shaped graft copolypeptides were synthesized using readily available alcohols as the initiators to perform ring-opening polymerization (ROP) promoted by 1,1,3,3-tetramethylguanidine (TMG), followed by deprotection and side chain modification. The introduction...
Polyhedral Oligomeric Silsesquioxanne (POSS) moieties are tethered on a polyurethane chain, as side groups on the hard domains, which are based on the flexible hexamethylene diisocyanate (HDI). Their effect on morphology, and consequently on molecular dynamics, is studied in detail by microscopy, scattering, spectroscopic, thermal, and dielectric techniques. Albeit the PU micromorphology does not...
The evolution of crystalline domain orientation vs. mechanical properties of aramid fibers under mechanical loading was investigated for initial crystalline domain orientations between 16.7° and 9.7°. The latter resulted in a broad range of longitudinal moduli between 66 GPa and 119 GPa but tensile strengths in the narrow range of 3.5–4.0 GPa. Mechanical conditioning up to 90% of the fiber tensile...
We present a high-resolution study of the viscoelastic response of a thermoplastic alloy using a multifrequency method called intermodulation atomic force microscopy. We quantitatively characterize the response in terms of calibrated dynamic force quadrature curves, showing the conservative and dissipative forces at each image pixel as functions of the oscillation amplitude for industrial polymer...
Dispersion in polymer nanocomposites is determined by the kinetics of mixing and chemical affinity. Compounds like reinforcing filler/elastomer blends display some similarity to colloidal solutions in that the filler particles are close to randomly dispersed through processing. It is attractive to apply a pseudo-thermodynamic approach taking advantage of this analogy between the kinetics of mixing...
Three fully π-conjugated bisterpyridines with fluorene unit in the central block were synthetized using the Suzuki–Miyaura coupling and transformed to corresponding conjugated metallo-supramolecular polymers (MSPs) with Zn2+ or Fe2+ ions. Assembling course of MSPs was investigated by absorption and emission spectroscopy, size-exclusion chromatography and viscometric measurements. Two systems with...
Novel fast-responding shape-memory polyurethanes were prepared from bio-based polyols, diphenyl methane diisocyanate and butane diol for the first time. The bio-based polyester polyols were synthesized from 9-hydroxynonanoic acid, a product obtained by ozonolysis of fatty acids extracted from soy oil and castor oil. The morphology of polyurethanes was investigated by synchrotron ultra-small angle...
We introduce a two-step strategy for the synthesis of linear polyglycerols (linPG-OHx/OMey) with an adjustable degree of methylation (y=DM100). Ethoxy ethyl glycidyl ether (EEGE) and glycidyl methyl ether (GME) were copolymerized via the “activated monomer” polymerization technique, using tetraoctylammonium bromide (NOct4Br) as an initiator and triisobutylaluminum (i-Bu3Al) as a catalyst under mild...
We report the preparation of cross-linked poly(l-lysine) (PLL), polyethylene glycol-block-poly(l-lysine) (PEG-b-PLL), and poly(l-lysine)-block-polysarcosine (PLL-b-PSar) gel particles with size ranged between 100 and 250 nm by emulsion and their evaluation as carriers/encapsulants for protein encapsulation/delivery. Their size and solution property were depended upon polymer molecular weight, composition,...
Novel azosystems possessing chemical architecture that allows for noncovalent attachment of the azobenzene or azopyridine chromophores to poly(ester imide) matrix via hydrogen bonding were fabricated. Chosen physicochemical properties including the ability of the chromophores to realign upon linearly polarized light were determined and discussed in relation to details of the materials structure. Calculations...
Resorcinol and formaldehyde reactions were quantitatively monitored by means of 1H and 13C NMR spectroscopy at room temperature (293 K) before heat treatment leading to formation of organic gels. We found that resorcinol substitution with formaldehyde starts with an initial surprisingly rapid step followed by a more gradual depletion of the reactants. Substituted species with both monomeric and dimeric...
Polymersomes, vesicles self-assembled from amphiphilic block copolymers, are well known for their robustness and for their broad applicability. Generating polymersomes of different shape is a topic of recent attention, specifically in the field of biomedical applications. To obtain information about their exact shape, tomography based on cryo-electron microscopy is usually the most preferred technique...
The stabilization of water/air, water/oil and water/solid interfaces by Janus particles with polystyrene (PS) and poly(methacrylic acid) (PMAA) hemispheres was systematically investigated. The stabilization of these interfaces is of relevance for the formulation of foams, emulsions and dispersions. The Janus particles were prepared from micellar solutions of polystyrene-b-polyisoprene-b-poly(tert-butyl...
This paper describes a strategy for preparing photosensitive polymeric grafts on flat solid surfaces by loading diblock-copolymer or homopolymer brushes with cationic azobenzene-containing surfactants. In contrast to previous work, we utilize photosensitive surfactants that bear positively-charged polyamine head groups whose charge varies between 1+ and 3+. Poly(methylmethacrylate-b-methacrylic acid)...
This paper addresses the relation between gold nanoparticle (AuNP) distribution in thermoresponsive polymer brushes and the thermally induced color change of the polymer brush/AuNP hybrids. Therefore, we report on the effect of AuNP surface functionalization on the structure and optical response of the nanoparticles in thermoresponsive poly(N- isopropylacrylamide) (PNIPAM) brushes. Two different types...
The reinforcement effects of two dimensional (2-D) few layer graphene (FLG) and one dimensional (1-D) multi-walled carbon nanotubes (MWCNT) in acrylonitrile-butadiene-styrene (ABS) were investigated using tensile testing machine. Both, FLG and MWCNT were dispersed well in ABS matrix but preferably reside in the styrene-acrylonitrile phase rather than in the polybutadiene phase. The reinforcement tendency...
The high strain-rate rheological and mechanical properties of bi-modal epoxy polymer networks were characterized using molecular dynamics simulation. The complex Young's modulus was found by applying a cyclic sinusoidal strain over a wide range of temperatures spanning the glass transition. The non-linear stress response was studied in the glass transition region using uni-axial deformation. We discuss...
We report the preparation of biocompatible, dual stimuli-sensitive lipoic acid-modified poly(l-lysine) (PLL-g-Lipo) hydrogels/nanogels by chemical cross-link and polypeptide/silica hybrid hydrogels/nanogels by simply depositing silica in the gel matrix. Hydrogels were prepared by ethylene oxide sterilization through the formation of inter-/intramolecular disulfide cross-link. Their gelation and mechanical...
We present a very simple polymer model of polyethylene glycols/oxides in water that can be used in combination with Molecular Dynamics or Monte Carlo simulations to accurately reproduce the equation of state and radii of gyrations across several orders of magnitude, in terms of osmotic pressure and polymer length. This is of importance for example in osmotic stress experiments, with the aim to accurately...
We report on rendering polyelectrolyte brushes photosensitive by loading them with azobenzene-containing cationic surfactants. Planar poly(methacrylic acid) (PMAA) brushes are synthesized using the “grafting from” free-radical polymerization scheme followed by exposure to a solution of photosensitive surfactants consisting of positively-charged head groups and hydrophobic tails into which azobenzene...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.