The synthesis of a series of benzofulvene derivatives 3 related to the recently studied ethyl 1-methylene-3-(4-methylphenyl)-1H-indene-2-carboxylate (BF1) is described. The properties of these trans-diene derivatives were characterized with regard to their capability of polymerizing spontaneously to give new polymers based on functionalized indene monomeric units. The series of polymers has been investigated by NMR spectroscopy, multiangle light scattering online to size exclusion chromatography, UV-vis spectroscopy, mass spectrometry, differential scanning calorimetry, and scanning electron microscopy. The new polymers show very interesting properties such as a thermoreversible polymerization/depolymerization, a variable degree of π-stacking, a tendency to give nanostructured macromolecular aggregates, and a high solubility in the most common organic solvents. Remarkably, this study demonstrated that most of the polymer properties (e.g. formation, molecular weight, structure, thermoreversibility, and aggregation in nanostructured entities) may be modulated by the stereoelectronic characteristics of the substituents present on the indene moiety.
PVA based hydrogels were synthesised using, as crosslinking agent, trisodium trimetaphosphate (STMP) to obtain potential substitutes for the vitreous body of the eye. The hydrogels, obtained using different amounts of STMP, were characterised by Infrared Spectroscopy which confirmed the successful occurrence of crosslinking reaction. The mechanical spectra of the fully hydrated samples confirmed covalently crosslinked systems (i.e. G' > G''). The rheological analysis pointed out that only one of the hydrogels (PVA STMP 8:1) showed a behaviour similar to that of human vitreous. The hydrogel was also subjected to injection through a small needle, a procedure that is essential in the use of vitreous substitutes. Further analysis in terms of light transmittance, water content measurements, diffusion coefficient and cytotoxicity confirmed the applicability of such a hydrogel as vitreous substitute.
Two methyl end-capped oligo(ethylene glycol) esters (1a,b) of benzofulvene derivative BF1 were synthesized and induced to polymerize spontaneously by solvent removal to give poly-1a,b showing both NMR and absorption/emission spectra very similar to those of poly-BF1. Poly-1a,b showed relatively high molecular weight and the tendency to depolymerize to a different degree as a function of the temperature in the presence of solvents, while they exhibited appreciable stability in the absence of solvent. Poly-1b, bearing a longer oligo(ethylene glycol) side chain, featured an amphiphilic character and interacted with a number of organic solvents to produce transparent gel aggregates, and with water to give a quite compact physical gel. Rheological studies performed on the hydrogel suggested strong gel characteristics and the combination of rheology and NMR transverse relaxation measurements allowed the pore size distribution in the hydrogel to be defined. Finally, biological studies performed with poly-1b solutions showed neither cytotoxicity nor cell viability impairment suggesting potential biocompatibility features for this polymer. In conclusion, poly-1b can be considered a promising polymer for the preparation of hydrogels potentially useful in a range of biological and biotechnological applications such as drug delivery, molecular recognition, biosensing, protein and DNA separation, micro-and nanofluidics, as well as tissue engineering.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.