Salvatore Battiato

Perfluorinated polymer with unexpectedly efficient deep blue electroluminescence for full-colour OLED displays and light therapy applications

The fluorinated phenylene unit is used as a building block for an all-conjugated fluorene-based alternating copolymer (PFO–TFP). The synthesis, carried out by an optimized Suzuki cross-coupling, produces an extremely high purity compound with a series of intriguing properties. Firstly, a blue-shift of the absorption and emission spectra with respect to the parent polymer is achieved. Secondly, the photoluminescence (PL) quantum yields (QYs) of the solution, as high as 68%, are surprisingly retained in the solid-state. Finally, an improved colour stability of the film with respect to unsubstituted polymers, investigated by means of cyclic voltammetry and exposure to ultraviolet radiation, is observed. The PFO–TFP tested as an undoped active layer in a polymer light-emitting diode (PLED) shows a highly desirable pure deep blue 405 nm electroluminescence, CIE = (0.17; 0.06) and a remarkable 5.03% external quantum efficiency, thus fulfilling the requirements for both full-colour displays and biomedical applications. To date, fluorine atom incorporation has been successfully employed in the synthesis of high-performing polymers for organic field-effect transistors and photovoltaics. We give the first unambiguous proof of its efficacy in achieving pure deep blue electroluminescence in a highly efficient and stable PLED, which is competitive with the best reported conjugated oligomer-based devices.

A Click Chemistry-Based “Grafting Through” Approach to the Synthesis of a Biorelevant Polymer Brush

A new biorelevant polymer brush showing a polybenzofulvene backbone was synthesized by a “grafting through” approach based on click chemistry and spontaneous polymerization reactions. The easy polymerization of the relatively complex monomer (6-MOEG-9-TM-BF3k) suggests the existence of a particularly efficient recognition process capable of pre-organizing the monomer molecules for the spontaneous polymerization. 13C-NMR spectroscopy as well as UV-vis and fluorescence spectroscopy suggested for poly-6-MOEG-9-TM-BF3k the features of a vinyl (1,2) π-stacked polymer. The new polybenzofulvene derivative was found to interact with water at room temperature to give clear water solutions, but TEM analysis demonstrated the presence of macromolecular aggregates showing dimensions larger than those suggested by SEC-MALS analysis for the isolated macromolecules. DLS studies confirmed the presence of objects showing average dimensions in the range of 200–300 nm and suggested thermoresponsive colloidal properties for poly-6-MOEG-9-TM-BF3kmacromolecules. Finally, owing to its favourable absorption/emission properties and water solubility, the interaction of poly-6-MOEG-9-TM-BF3k with live cells was studied by fluorescence microscopy experiments, which revealed that the polymer brush was unable to enter live cells and alter cell morphology.

Bithiophene-based polybenzofulvene derivatives with high stacking and hole mobility

Four new benzofulvene derivatives bearing bithiophene chromophores at two different key positions of the phenylindene scaffold were prepared in order to evaluate the role of different chromophores in the optoelectronic features of polybenzofulvene derivatives. The results of the photophysical studies showed that the optical properties of the newly-synthesized bithiophene-functionalized polymers were affected by both the polymer enchainment and the substitution topology of the monomeric units. On the other hand, the hole-mobility appeared to be affected to a lesser extent, but the best performances were obtained in poly-6-HBT-BF3k showing the strongest bithiophene side chain packing. This work demonstrates that the optoelectronic properties of polybenzofulvene derivatives can be optimized by a targeted chemical design such as side chain engineering.

Hyaluronan-coated polybenzofulvene brushes as biomimetic materials

Hyaluronic acid (HA) forms pericellular coats in many cell types that are involved in the early stages of cell adhesion by interacting with the CD44 receptor. Based on the largely recognized overexpression of the CD44 receptor in tumor tissues, a polybenzofulvene molecular brush has been enveloped into hyaluronan shells to obtain a tri-component polymer brush (TCPB) composed of intrinsically fluorescent backbones bearing nona(ethylene glycol) arms terminated with low molecular weight HA macromolecules. The nanoaggregates obtained in TCPB water dispersions were characterized on the basis of dimensions, zeta potential, and in vitro cell toxicity. This biomimetic multifunctional material bearing HA on the surface of its cylindrical brush architecture showed promising prerequisites for the preparation of nanostructured drug delivery systems.

Synthesis, Characterization, and Properties of New Phosphorus-Containing Epoxy Resins

Abstract Four new phosphonate-epoxy monomers were synthesized and characterized by 1H and 31P-NMR, matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS), thermal gravimetric analysis (TGA), and differential scanning calorimetry (DSC) tools. Beside the expected compund, the formation of a small amounts of linear oligomers was also observed by MALDI-TOF MS. These monomers were used to prepare new phosphorus-containing epoxy resins in order to obtain potential flame retardant polymers. The thermal behavior of these new epoxy resin was studied by DSC, TGA, and direct pyrolysis mass spectrometry (DPMS). TGA and DPMS data show that either the maximum decomposition temperature (PDT) or the onset of the thermal degradation of the phosphorus-containing epoxy resins is lower than that of the corresponding nonphosphonate samples. GRAPHICAL ABSTRACT

Poly-histidine grafting leading to fishbone-like architectures

A small series of Morita–Baylis–Hillman adduct (MBHA) derivatives was synthesized and made to react with imidazole, N-acetylhistidine, and N-acetylhexahistidine as models of poly-histidine derivatives. Intriguingly, the reaction of MBHA derivatives 1a and b with imidazole in acetonitrile–phosphate buffered saline (PBS) gave the imidazolium salt biadducts 3a and b as the main reaction products. These results were confirmed by experiments performed with N-acetylhistidine and 1b and suggested the possible occurrence of these structures in the products of poly-histidine labeling with MBHA derivatives 1a and b. These compounds were then transformed into the corresponding water-soluble derivatives 1c–e by introducing oligo(ethylene glycol) chains and their reactivity was evaluated in preliminary experiments with imidazole and then with N-acetylhexahistidine in PBS. The structure of polymeric materials Ac-His-6-MBHA-1d and Ac-His-6-MBHA-1e obtained using ten-fold excesses of compounds 1d and e was investigated using mass spectrometry, NMR spectroscopy, and photophysical studies, which suggested the presence of biadduct residues in both polymeric materials. These results provide the basis for the preparation of fishbone-like polymer brushes, the characterization of their properties, and the exploration of their potential applications in different fields of science such as in vivo fluorogenic labeling, fluorescence microscopy, protein PEGylation, up to the production of smart materials and biosensors.

Synthesis and Characterization of Linear Hyperbranched PBA Block Copolymers, as Potential Polymeric Plasticizers

Linear hyperbranched block copolymers based on PBA polyesters (HPBA) has been synthesized by a one‐pot synthesis procedure and well characterized by MALDI‐TOF mass spectrometry, H‐NMR and SEC tools, to obtain reliable information on its chemical composition and molar mass distribution.

Synthesis and characterization of poly(4-oxyalkylenoxy benzoate)s of different chain length

Abstract Three different monomers starting from p-(4-hydroxy)benzoic acid and 3- chloro-1-propanol, 4-chloro-1-butanol and 6-chloro-1-hexanol, respectively, were synthesized and extensively characterized by means of 1H and 13C NMR, MALDITOF MS and elemental analysis. Subsequently, poly(4-oxyalkylenoxy benzoate)s polymers with different chain length were prepared in bulk starting from the mentioned above monomers, employing Ti(OBu)4 as catalyst, according to the usual two-stage polymerization procedure. The polymers were characterized in terms of chemical structure, molecular mass and thermal behaviour. Tg, Tm and the ability to crystallize were found to be affected by the number of methylene groups per repeat unit and the results were explained mainly on the basis of the increment of the chain flexibility.