We here report the synthesis of a new class of carbohydrate-based block copolymers, poly(3-hexylthiophene)-block-peracetylated maltoheptaose (P3HT-b-AcMal 7 ) and poly(3-hexylthiophene)-block-maltoheptaose (P3HT-b-Mal 7 ), and their bulk and self-assembled thin films morphological characterizations by atomic force microscopy, transmission electron microscopy, and small-angle X-ray scattering. The block copolymers were synthesized via copper(I)-catalyzed 1,3-dipolar azide−alkyne cycloaddition of azido-functionalized AcMal 7 and end-functionalized P3HT with alkyne group prepared by modified Grignard metathesis polymerization, followed by deacetylation of the AcMal 7 block. The half-pitch of sub-10 nm scale lamellar structures, one of the smallest domain sizes of microphase separated block copolymers reported to date, was self-organized in the bulk and thin films of P3HT-b-AcMal 7 by thermal annealing above the melting temperature of the P3HT segment. Meanwhile, thermodynamic microphase separation of P3HT-b-Mal 7 was restricted due to strong inter-and intrachain hydrogen bonding among the hydroxyl groups of the Mal 7 block, which was confirmed by an in situ stepwise heating and cooling Fourier transform infrared spectroscopy study.
Amphotericin B (AmB) is the drug of choice in the treatment of invasive fungal infections and visceral leishmaniasis. Although AmB has a higher selectivity for ergosterol (present in fungi and Leishmania spp. membrane) than for cholesterol, mammalian cells are affected by AmB, mainly in its oligomeric aggregated form, resulting in side effects, especially nephrotoxicity. The development of nanotechnology-based drug delivery systems for AmB is a promising avenue since nanoparticles have the ability to target drugs to the infected cells, and their prolonged drug release profile permits longer contact between the drug and the fungi/parasite. In this review, we made an overview about nanoparticles as colloidal carriers for AmB, including polymeric-based nanoparticles, protein-based nanoparticles and solid lipid-based nanoparticles with respect to their application for the treatment of invasive fungal infections and leishmaniasis.
Epoxy anhydride networks were modified with Siloxane/PMMA hybrid materials, obtained from sol/gel method. The effects of thermal annealing of the Siloxane/PMMA hybrids and of the hybrid composition on the nanostructure of the epoxy network were investigated by means of SAXS. The composites containing Siloxane/PMMA materials with low amount of MMA present a hierarchical nanostructure whose first level is made of siloxane nanoparticles spatially correlated in the matrix forming larger secondary hybrid aggregates. Small amounts of hybrid material decrease the glass temperature of the composite, but increase the storage modulus, indicating its nanoreinforcing action.magnified image
Organic
dyes have been studied for applications in large-area,
flexible, cheap, and efficient organic electronic devices. Among them,
diketopyrrolopyrrole (DPP) has gained attention thanks to its planar
structure, photochemical and thermal stability, and easy processability.
Also, the electron-withdrawing nature of DPP makes its application
attractive in the synthesis of donor–acceptor (D–A)
copolymers, with appealing features such as the tunable energy levels
and photophysical and electrochemical properties. Inspired by these
exciting characteristics, a copolymer was developed based on DPP,
thiophene, and fluorene (PFDPP2T). Photophysical and electrochemical
studies using both experimental and theoretical approaches were performed
aiming to understand the properties of this material, such as, for
instance, the D–A characteristic and the outstanding electrochemical
stability upon oxidation that enables more than 400 cycles of p-doping.
The outcomes unveil fundamental aspects of this class of copolymers,
reinforcing their suitability for photo-electrochemical and optoelectronic
applications.
Abstract.A new class of organic-inorganic hybrid nanocomposites was obtained by blending PMMA-modified silsesquioxane hybrid materials with epoxy matrix followed by curing with methyl tetrahydrophthalic anhydride. The hybrid materials were obtained by sol-gel method through the hydrolysis and polycondensation of the silicon species of the hybrid precursor, 3-methacryloxypropyltrimethoxysilane (MPTS), simultaneously to the polymerization of the methacrylate (MMA) groups covalently bonded to the silicon atoms. The nanostructure of these materials was investigated by small angle X-ray scattering (SAXS) and correlated to their dynamic mechanical properties. The SAXS results revealed a hierarchical nanostructure consisting on two structural levels. The first level is related to the siloxane nanoparticles spatially correlated in the epoxy matrix, forming larger hybrid secondary aggregates. The dispersion of siloxane nanoparticles in epoxy matrix was favored by increasing the MMA content in the hybrid material. The presence of small amount of hybrid material affected significantly the dynamic mechanical properties of the epoxy networks.
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