Search results for "Elf"

An Unlockable-Relockable Iron Cage by Subcomponent Self-Assembly

2008

Aggregation processes of perylene bisimide diimidazolium salts

2015

The supramolecular aggregation of three diimidazolium- functionalized perylene bisimides, differing in the alkyl chain length was investigated. These salts form aggregates in solvents like chloroform, dichloromethane, and glycerol. Solvent-, concentration-, and temperature-dependent spectroscopic studies were carried out, evidencing the occurrence of an isodesmic, enthalpy-driven aggregation process, underpinned by p–p stacking and hydrogen bonding. Moreover, dynamic light scattering (DLS) measurements and SEM images revealed that these salts aggregate in chloroform into elongated structures.

Self-assembly of fluorescent diimidazolium salts: tailor properties of the aggregates changing alkyl chain features

2016

Searching for new fluorescent organic salts to be used in biomedical and electrochemical field, we conjugated properties of imidazolium salts with the ones of naphthalene diimide core and we obtained some N,N′-bis-(1-alkyl-3-propylimidazolium)naphthalene diimide diiodides. We took into account alkyl chains going from hexyl to dodecyl, as well as hydrogenated and fluorinated alkyl tails. After determination of their thermal behaviour by differential scanning calorimetry, concentration-, and temperature-dependent spectroscopic studies (UV-vis and fluorescence) were performed evidencing the occurrence of isodesmic and enthalpy-driven self-assembly processes. Properties of aggregates were also …

In situ forming hydrogels of new amino hyaluronic acid/benzoyl-cysteine derivatives as potential scaffolds for cartilage regeneration

2012

A new chemical strategy is described to link ethylenediamino (EDA) groups to primary hydroxyl groups of hyaluronic acid (HA) and the obtained derivatives have been characterized by 1H-NMR and 13C-NMR analyses. Such HA–EDA derivatives have been exploited to control the functionalization degree in benzoyl-cysteine (BC) groups, chosen as moieties able to allow both self-assembling in aqueous media and an oxidative crosslinking. In particular, the kinetics of oxidation of thiol groups in HA–EDA–BC derivatives has been studied in Dulbecco's Phosphate Buffer Solution (DPBS) pH 7.4 by colorimetric assays and rheological measurements. Mechanical properties of chemical hydrogels obtained after oxida…

α,β-Poly(N-Hydroxyethyl)-DL-Aspartamide Hydrogels as Drug Delivery Devices

1996

α,β-poly(N-hydroxyethyl)-DL-aspartamide (PHEA) was exposed to gamma radiation to obtain micromatrices able to swell in an aqueous medium. Crosslinked PHEA was loaded with an anti-inflammatory drug, 4-biphenylacetic acid (BPAA) and the drug dispersion in the network was investigated by X-ray analysis. The BPAA loaded PHEA microparticles were also characterized by dimensional analysis, which showed the presence of quasispherical shapes. The drug release from PHEA hydrogel was studied in vitro in a pH 1.1 (simulated gastric juice) and in a pH 7.4 buffer solution, respectively. The experimental data indicate that an anomalous delivery occurs, but Fickian diffusion through swollen PHEA hydrogel…

Magnetic Composite Thin Films of FexOy Nanoparticles and Photocrosslinked Dextran Hydrogels

2012

Abstract Magnetic hydrogel composites are promising candidates for a broad field of applications from medicine to mechanical engineering. Here, surface-attached composite films of magnetic nanoparticles (MNP) and a polymeric hydrogel (HG) were prepared from magnetic iron oxide nanoparticles and a carboxymethylated dextran with photoreactive benzophenone substituents. A blend of the MNP and the dextran polymer was prepared by mixing in solution, and after spin-coating and drying the blend film was converted into a stable MNP–HG composite by photocrosslinking through irradiation with UV light. The bulk composite material shows strong mobility in a magnetic field, imparted by the MNPs. By util…

Inulin vinyl sulfone derivative cross-linked with bis-amino PEG: new materials for biomedical applications

2009

In this work new hydrogels based on biocompatible polymers such as inulin (INU) and O,O'-bis(2-aminoethyl)polyethyleneglycol (PEGBa) have been prepared and charaterized. In particular, INU has been derivatized with divinyl sulfone (DV) thus obtaining the INUDV derivative, a copolymer bearing double bonds highly reactive towards the conjugate addition by nucleophilic molecules. INUDV has been characterized by FT-IR, 1 H-NMR and SEC analyses that have confirmed the success of the derivatization reaction. With the aim to obtain novel hydrogel systems, INUDV derivative has been cross-linked with PEGBa in phosphate buffer solution pH 7.4. The reaction has been carried out for 4 h at room tempera…

Structural and Gelation Characteristics of Metallo-Supramolecular Polymer Model-Network Hydrogels Probed by Static and Dynamic Light Scattering

2021

Supramolecular polymer gels are a promising class of materials whose polymer components are connected by transient bonds such as metal–ligand interactions, thereby spanning a dynamic network throug...

Reactive nanorods based on activated esterpolymers: a versatile template-assisted approach for the fabrication of functional nanorods

2011

A new route for the fabrication of polymeric nanorods with functional moieties via post-modification of reactive nanorods is described. To this end reactive nanorods with a homogenous and narrow size distribution were fabricated by utilizing an anodic aluminium oxide (AAO) template-assisted approach. The nanorods are based on activated pentafluorophenyl esters, to enable quantitative post-modification with amines under very mild reaction conditions yielding the corresponding functionalized amide. Post-modification with fluorescent dyes as well as the conversion into well-dispersed rod-shaped poly(N-isopropylacrylamide) (PNIPAM) hydrogels that exhibit a thermal-responsive phase transition wa…

Structure Formation of Polymeric Building Blocks: Complex Polymer Architectures

2013

This chapter describes macromolecules with a complex structure, their defined aggregation in solution, their adsorption to surfaces, and their possible aggregation on surfaces. The term “complex structure” implies that the macromolecules show different, distinct structural elements or building blocks on a supra-atomic length scale. Key to understanding the complex structure of macromolecules, their aggregation, and adsorption to surfaces are intra- and intermolecular interactions such as van der Waals, electrostatic, π–π interactions, and hydrogen bonds.