Non-traditional intrinsic luminescence: inexplicable blue fluorescence observed for dendrimers, macromolecules and small molecular structures lacking traditional/conventional luminophores

Polyhedral oligomeric silsesquioxane meets “click” chemistry: Rational design and facile preparation of functional hybrid materials

Although used in medical applications for centuries, the development of nanotechnology has shed new light in the plethora of possible medical and biological applications using gold-based nanostructures. Gold nanostructures are stable and relatively inert in biological systems, leading to low reatogenicity, biocompatibility and general lack of toxicity. Allied to that, gold nanoparticles present optical and electronic properties that have been exploited in a range of biomedical applications. In this review we discuss biologically relevant properties of gold nanoparticles and how they are used in some biomedicine fields, especially those involving biosensing of biological analytes – including viruses and antibodies against them, cancer therapies, and antigen delivery, including viral antigens – as part of nonclassic vaccine strategies.

Gold nanoparticles and their applications in biomedicine

This work presents a simple and reliable method for directly generating polyvinylidene fluoride (PVDF) nanofibers with secondary surface morphology (e.g., porous surfaces, rough surfaces, grooved surfaces, and interior porosity) by using single/binary solvent systems and relative humidity. We clarified the mechanisms responsible for the formation of these morphologies by systematically exploring the molecular interactions among the polymer, solvent(s), and water vapor. Our results proved that the formation of secondary surface morphology needed the presence of water vapor, a non-solvent of the polymer, at an appropriate level of relative humidity. The formation of secondary surface morphology was dependent on the speed of evaporation of the solvent(s) (ACE, DMF, and their mixtures), as well as the inter-diffusion and penetration of the non-solvent (water) and solvent(s). The results of N2 physical adsorption-desorption isotherms showed that the macro-porous fibers (> 300 nm) exhibited the highest specific surface area of 23.31 ± 4.30 m2/g and pore volume of 0.0695 ± 0.007 cm3/g, enabling the high oil absorption capacities of 50.58 ± 5.47 g/g, 37.74 ± 4.33 g/g, and 23.96 ± 2.68 g/g for silicone oil, motor oil, and olive oil, respectively. We believe this work may serve as guidelines for the formation of different structures of macro-porous, rough, and grooved nanofibers with interior porosity through electrospinning.

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Controlling the Secondary Surface Morphology of Electrospun PVDF Nanofibers by Regulating the Solvent and Relative Humidity.

Surface modification of fibers has attracted significant attention in different areas and applications. In this work, polyvinylidene fluoride (PVDF) cactus-like nanofibers were directly produced via electrospinning at a high relative humidity (RH) of 62%. The formation mechanism of the cactus structure was demonstrated. The effects of the RH on the fabrication of the cactus structure, crystalline phases, mechanical properties, hydrophobicity, and piezoelectric properties of the PVDF nanofibers were investigated. The results showed that the cactus-like nanofibers have a high crystallinity (ΔXc), and an outstanding water contact angle (WCA), as well as good electrical outputs. We believe that the PVDF cactus structure can be used in many applications such as energy harvesting and self-cleaning surfaces.

/pdf/fabrication-of-a-polyvinylidene-fluoride-cactus-like-1d65u46l2i.pdf

Fabrication of a polyvinylidene fluoride cactus-like nanofiber through one-step electrospinning

New star poly(N-isopropylacrylamide)-b-polyhedral oligomeric silsesquioxane (PNIPAm-b-POSS) copolymers were synthesized from octa-azido functionalized POSS (N3-POSS) and alkyne-PNIPAm, which was prepared using an alkyne-functionalized atom transfer radical polymerization (ATRP) initiator (propargyl 2-bromo-2-methylpropionamide), via click chemistry. These star PNIPAm-b-POSS copolymers undergo a sharp coil-globule transition in water at above 32°C changing from a hydrophilic state below this temperature to a hydrophobic state above it, which is similar to linear PNIPAm homopolymers. More interestingly, we found that these star polymers exhibited strong blue photoluminescence in water above a lower critical solution temperature (LCST). This photoluminescence was likely due to the constrained geometric freedom and relatively rigid structure caused by intramolecular hydrogen bonding within the star PNIPAm polymers, which exhibit an intrinsic fluorescent behavior.

/pdf/star-poly-n-isopropylacrylamide-tethered-to-polyhedral-40ef4u0stv.pdf

Star poly(N-isopropylacrylamide) tethered to polyhedral oligomeric silsesquioxane (POSS) nanoparticles by a combination of ATRP and click chemistry

The development of novel catalysts for degrading organic contaminants in water is a current hot topic in photocatalysis research for environmental protection. In this study, C3N5 nanosheet/Ag2CO3 nanocomposites (CNAC-X) were used as efficient photocatalysts for the visible-light-driven degradation of methylene blue (MB), and tetracycline hydrochloride (TC-HCl) was synthesized for the first time using a simple thermal oxidative exfoliation and in situ deposition method. Due to the synergistic effect of nanosheet structures, carbon defects, and Z-scheme heterojunctions, CNAC-10 exhibited the highest photocatalytic activity, with photodegradation efficiencies of 96.5% and 97.6% for MB (60 mg/L) and TC-HCl (50 mg/L) within 90 and 100 min, respectively. The radical trapping experiments showed that ·O2− and h+ played major roles in the photocatalytic effect of the CNAC-10 system. Furthermore, intermediates in the photodegradation of MB and TC-HCl were investigated to determine possible mineralization pathways. The results indicated that C3N5 nanosheet/Ag2CO3 photocatalysts prepared in this work could provide an effective reference for the treatment of organic wastewater.

/pdf/in-situ-coupling-carbon-defective-c3n5-nanosheet-with-ag2co3-2z3nk9tc.pdf

In Situ Coupling Carbon Defective C3N5 Nanosheet with Ag2CO3 for Effective Degradation of Methylene Blue and Tetracycline Hydrochloride

This study provides an insight into the foaming of thermoplastic polyurethane (TPU), which was improved by the crystallization of hard segment domains. This study investigated the effects of packing time in the mold-opening foam injection molding (MOFIM) technology on the crystallization behavior of hard segments in TPU and the cell morphology of TPU foams. It was observed that the prolongation of the packing time, corresponding to a longer crystallization time before foaming, induced an increased crystallinity in the injection-molded TPU solids and foams due to the crystals becoming more close-packed. The enhancement of the foamability of TPU was attributed not only to the increased crystallinity of hard segments, but also to the broader distribution of crystals at the same crystallinity. Furthermore, TPU foams with greater hardness have smaller cell size, higher cell density, and narrower distribution in cell size owing to their higher viscosity and storage modulus than those with lower hardness prepared under the same conditions. 

Enhanced foaming ability of thermoplastic polyurethane by crystallization during mold-opening foam injection molding with supercritical N2 as blowing agents

Jing-Long Hong

Papers

Star poly(N-isopropylacrylamide) tethered to polyhedral oligomeric silsesquioxane (POSS) nanoparticles by a combination of ATRP and click chemistry

In Situ Coupling Carbon Defective C3N5 Nanosheet with Ag2CO3 for Effective Degradation of Methylene Blue and Tetracycline Hydrochloride

Enhanced foaming ability of thermoplastic polyurethane by crystallization during mold-opening foam injection molding with supercritical N2 as blowing agents