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Sensitized triplet-triplet annihilation-based photon upconversion is a photo-physical process that affords anti-Stokes-shifted emission after annihilation of two metastable triplet excitons of an emitter dye and the formation of a fluorescent singlet state. While this process readily occurs in solutions under conditions where the mobility of the dye molecules is high, particular architectures are required to facilitate efficient energy transfers in solid polymers. One possibility is to incorporate liquid upconverting domains into solid polymer matrices. Another possibility is to reduce the intermolecular distance between the dyes below the Dexter radius, allowing exciton migration via triplet hopping. We introduce herein nanostructured materials that combine both of these features. These glassy nanostructured polymer systems contain liquid upconverting nanodroplets that are stabilized with a block copolymer surfactant and are fabricated under ambient conditions in a facile one-step protocol. The dyes concentrate in the nanostructured liquid domains, and this enables hopping-mediated ET and TTA between the dyes and leads to an upconversion efficiency of similar to 20%.

In these years a variety of polymeric nanocarriers such as dendrimers, polymeric micelles, nanoparticles, nanogels, nanocapsules and vesicles are widely investigated as potential drug delivery systems. In addition to the different morphologies and sizes, these carriers may have on their surfaces specific functionalizations to improve the drug loading and controlled release and specific ligands for cell receptors, in order to achieve a precise targeting. This review focuses on recent functionalized polymeric nanomaterials used as drug delivery systems, with an emphasis on morphology and surface modifications of polymeric nanocarriers to improve controlled drug delivery. Moreover, this work offers a number of suggestions on how to achieve the systematization of data on the most relevant physico-chemical parameters, which govern and control the interaction between carrier and drug, with the aim to give the reader an overview of the most significant advances in this field. Keywords: Nanostructured polymers, Drug delivery systems, Dendrimers, polymeric micelles, Polymeric nanoparticles, Nanogels, Polymeric nanocapsules, Vesicles

One of the major challenges of Life Cycle Assessment is in the generation of life cycle inventories for complex or novel materials. This paper aims at broadening the perspective in Life Cycle Assessment methodology, exploiting multiscale modelling towards the generation of inventory data during an early-stage product design. Our approach involves the usage of molecular modelling techniques, such as electronic, atomistic or mesoscale models, in combination with continuum models, such as process simulation or finite element methods, to provide data for the generation of life cycle inventories of nanostructured materials. In particular, each simulation is performed at a specific length and time scale through specific software, passing information from the lower to the upper scale. We applied our procedure to a comparative Life Cycle Assessment among suitable materials for the production of a set of cylinder head cover of a marine engine, i.e., aluminium alloys and nano-engineered thermoplastic polymers. Engineering judgment, Ashby charts and maritime regulations led the initial identification of suitable materials. As a result, polyamide 6,6 reinforced with 30% wt. glass fibers and mixed with phosphate-based flame retardants have been identified as promising candidate for the replacement of aluminium traditional covers. Nonetheless, we introduced nanoclays, i.e., exfoliated montmorillonite, as a replacement for a quota of conventional flame retardant, aiming at reducing the usage of pollutant chemicals. We then resorted to atomistic and finite-element techniques to investigate the compliance of nanocomposite materials with several Key Performance Indicators. The nanocomposite formulations obtained from simulations have been finally employed as input data for life cycle inventories of material alternatives. Using a Life Cycle Assessment approach, we could identify the most environmental-friendly nanocomposite formulation, which was then compared with traditional aluminium through an additional comparative cradle-to-grave study. Among the suitable nanocomposite formulations, the material with the minimum amount of traditional flame retardant exhibited the lowest scores among the majority of Environmental Footprint impact categories. To account for the entire lifetime of the marine engine, a set of four nanocomposite covers has been compared with a set of three aluminium covers made by two different metal alloys. Four recycling scenarios for aluminium covers have been examined, assuming an incremental number of end-of-use products reintroduced into a circular life cycle, while nanocomposite ones were disposed into landfill. In turn, if the aluminium products are insufficiently recycled, our results promote the usage of nano-engineered polymer products. As the amount of reused metal covers increases, indeed, polymer-based covers become unfavorable with respect to aluminium cast alloy products. Accordingly, an increasing amount of post-consumer aluminium diminishes the need of primary metal, yielding considerable advantages in terms of environmental footprint. Consequently, stakeholders should commit in recycling metal components not only at ship dismantling, but also during ordinary maintenance. Our study showed how multiscale molecular modelling proved to be useful for providing necessary inventory data for complex nanostructured materials. This preliminary study paves the way for future development of the proposed framework, in which in-silico techniques based on distinct paradigms can mutually contribute towards an improvement of products ecodesign.

Photon upconversion based on sensitized triplet–triplet annihilation (sTTA-UC) is a wavelength-shifting technique with potential use in actuators, sensing, and solar technologies. In sTTA-UC, the upconverted photons are the result of radiative recombination of high-energy singlets, which are created through the fusion of metastable triplets of two annihilator/emitter molecules. The emitter triplets are populated via energy transfer (ET) from a low-energy absorbing light-harvester/sensitizer. The process is highly efficient at low powers in solution but becomes relatively ineffective in solid matrices since the limited molecular mobility precludes bimolecular interactions. The realization of efficient solid-state upconverters that exhibit long-term stability and are compatible with industrial fabrication processes is an open challenge. Here, nanophase-separated polymer systems synthesized under ambient conditions that contain the upconverting dyes in liquid nanodomains is reported. The nanostructured polymers show an excellent optical quality, an outstanding upconversion efficiency of up to ≈23%, and excellent stability in air, with only negligible performance losses over a period of three months. Moreover, the dyes’ confinement in nanosized domains

Nanostructured polymers, with different morphologies and different spatial organizations, have found, in last few years, a wide range of uses in humidity sensors, as a viable alternative to ceramic or semiconducting materials and to oxides (perovskite) compounds. Their enhanced sensitivity towards external stimuli has made them ideal candidates in the design of humidity sensors. This is mainly due to the fact that nanostructured polymers, when embedded with different content of water, represent a heterogeneous system whose dielectric and conductometric properties varies over a wide range, resulting in advantageous sensitive material in resistive-type or capacitive-type humidity sensors. The most notable property of nanostructured polymers is their inherent electrical behavior which is closely connected to the presence of heterogeneities at a nano- or micro-scale level. In the first part of this paper, we discuss and justify, on the basis of the dielectric theory of heterogeneous systems, how the dielectric properties of nanostructured polymers, independently of their chemical nature, could vary as a consequence of a different amount of water adsorption, meeting the basic requirement of any humidity sensor device. In particular, we have analyzed systems with different porosity and different pore interconnections to cover the most part of the structural arrangements and morphologies nanostructured polymers give rise. In the second part of the paper, we present some remarkable examples of nanostructured polymers employed in the fabrication of humidity sensors based on changes in the electrical properties (permittivity and electrical conductivity) upon exposure to moisture, highlighting the main features that make them suitable for sensors, with specific emphasis to characteristic parameters, such as sensitivity, response time, hysteresis and durability.

RNA interference (RNAi) is a powerful tool to treat diseases and elucidate target gene function. Prior to clinical implementation, however, challenges including the safe, efficient and targeted delivery of siRNA must be addressed. Here, we report cationic nanogel nanostructured polymers (NSPs) prepared by atom transfer radical polymerization (ATRP) for in vitro and in vivo siRNA delivery in mammalian models. Outcomes from siRNA protection studies suggested that nanogel NSPs reduce enzymatic degradation of siRNA within polyplexes. Further, the methylation of siRNA may enhance nuclease resistance without compromising gene knockdown potency. NSP-mediated RNAi treatments against Gapdh significantly reduced GAPDH enzyme activity in mammalian cell culture models supplemented with 10% serum. Moreover, nanogel NSP-mediated siRNA delivery significantly inhibited in vivo GFP expression in a mouse model. GFP knockdown was siRNA sequence-dependent and facilitated by nanogel NSP carriers. Continued testing of NSP/siRNA compositions in disease models may produce important new therapeutic options for patient care.

The most commonly used methods to electrodeposit nanomaterials on conductive supports or to obtain electrosynthesis nanomaterials are described. Au, layered double hydroxides (LDHs), metal oxides, and polymers are the classes of compounds taken into account. The electrochemical approach for the synthesis allows one to obtain nanostructures with well-defined morphologies, even without the use of a template, and of variable sizes simply by controlling the experimental synthesis conditions. In fact, parameters such as current density, applied potential (constant, pulsed or ramp) and duration of the synthesis play a key role in determining the shape and size of the resulting nanostructures. This review aims to describe the most recent applications in the field of electrochemical sensors of the considered nanomaterials and special attention is devoted to the analytical figures of merit of the devices.

Electrically conductive polypyrrole (PPy) was functionalized with heparin (Hep) to improve its surface biocompatibility. Heparin, which is a bioactive polyelectrolyte, was used as the doping anion. The immobilization of Hep in PPy was facilitated by the use of a nanoporous membrane which acts as templating substrate. In this way we have synthesized nanostructured electrodes based on polypyrrole and heparin as hollow tubules. The aim of this study was to determine the influence of the electrosynthesis parameters (monomer concentration and electrolyte nature) on the morphology and kinetics of the PPy nanomaterials in view of their possible, long-term biomedical applications.

This study was aimed at (1) developing new films based on polylactic acid/montmorillonite (PLA/MMT) with improved properties for applications in the food packaging industry and (2) analyzing the effect of electron-beam (eBeam) radiation on the structural, morphological, mechanical, and barrier properties of these nanomaterials. Nanocomposites based on PLA with 1, 3, and 5 wt % of MMT were prepared in a twin-screw extruder and then filmed by a calender. The nanocomposites were exposed to eBeam doses; one set at 1 kGy dose and the other at 10 kGy dose. The effect of MMT addition and of eBeam radiation on the properties of PLA were assessed. For all composites, a homogeneous distribution and dispersion of MMT in the PLA matrix was obtained. All nanocomposites showed an increase of the mechanical and oxygen-barrier properties compared to neat PLA. The eBeam irradiation caused an increase of the crystallinity, formation of crosslink, increase of the glass-transition temperatures, and enhancement of the yield values in the stress–strain curves for all nanocomposites. This study demonstrated that PLA/MMT films are suitable materials for eBeam processing of prepacked food at the realistic doses that were employed in this study. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42219.

Nanobiocomposites are a new class of biodegradable polymer materials with an ultrafine phase dispersion of the order of a few nanometers in a biodegradable polymer matrix that shows very interesting properties often very different from those of conventional filled polymers. In this work the morphology and the rheological and mechanical properties of a new nanobiocomposite made of a biodegradable copolyester based blend with an organomodified montmorillonite have been investigated to evaluate its possible use in several applications. SAXS diffractograms and TEM micrographs show that the in both the adopted processing conditions an hybrid intercalated/exfoliated morphology is observed. Rheological behavior is significantly influenced by the presence of the filler and more important, depends on the type of the applied type of flow. As for the mechanical properties, the elastic modulus strongly increases, while the elongation at break remarkably decreases. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42128.

This article deals with the investigation of electrical properties of epoxy-based nanocomposites containing graphene oxide nanofillers dispersed in the polymer matrix through two-phase extraction. Broadband dielectric spectroscopy and dc electrical conductivity as a function of electric field have been evaluated in specimens containing up to 0.5 wt % of nanofiller. Nanocomposites containing pristine graphene oxide do not show significant changes of electrical properties. On the contrary, the same materials after a proper thermal treatment at 135°C, able to provoke the in situ reduction of graphene oxide, exhibit higher permittivity and electrical conductivity, without showing large decrease of breakdown voltage. Moreover, a nonlinear behavior of the electrical conductivity is observed in the range of electric fields investigated, i.e. 2–30 kV mm−1. A new relaxation phenomenon with a very low temperature dependence is also evidenced at high frequency in reduced graphene oxide composites, likely associated to induced polarization of electrically conductive nanoparticles. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41923.

The article investigates the effects of long term environmental aging on thermal and mechanical properties of epoxy-silica hybrids. These nanostructured materials, prepared by non-aqueous sol-gel process and in situ generation of nanosilica during epoxy curing at room temperature, present the potential to be used as cold-cured adhesives for civil engineering and Cultural Heritage applications. A specifically developed conditioning procedure for these cold-cured nanostructured materials was applied before moisture/water absorption tests. The work evidenced the superior durability of the studied epoxy-silica hybrid, which kept its performances in severe, but realistic, environmental conditions with respect to traditional epoxy adhesives. The reduction in the glass transition temperature and mechanical properties of the studied epoxy-silica hybrid, observed in the first weeks of environmental aging, was followed by a significant recovery. This was attributed to two concomitant phenomena: the reactivation of the incomplete curing reactions in the epoxy domains and the continuation of the condensation reactions in the siloxane domains activated by the absorbed water. Finally, the Fickian behavior, presented by the studied epoxy-silica hybrid, was used as an indirect indication of the homogeneity of achieved microstructure, with well dispersed silica nanostructures in the epoxy network. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40093.

This review reports the promising prospects of poly(lactic acid) (PLA) based nanostructured materials considering two of their main potential uses, packaging and tissue engineering. The review initially discusses the significant progresses in the development of PLA bionanocomposites for packaging applications. The review then continues with a comprehensive analysis of the recent advances in tissue engineering applications focusing in the synthesis of PLA nanoparticles, the processing of PLA based multifunctional nanocomposites and PLA surface modification techniques. In summary, the review presents the current state of nanostructured PLA materials and establishes the exciting present and future prospects of these materials at the interface of chemistry, biology and material science., The authors gratefully acknowledge the financial support of the CSIC (2010MA0003). NB thanks the CSIC for a JAE-Pre grant. The Author Elena Fortunati is the recipient of the fellowship “L’Oreal Italia per le Donne e la Scienza 2012” for the project >Progettazione, sviluppo e caratterizzazione di biomateriali nanostrutturati capaci di modulare la risposta e il differenziamento delle cellule staminali>.

""Poly(phenylacetylene) (PPA) and poly(phenylacetylene-co-acrylic acid) (P(PA-co-AA)), nanoparticles bioconjugated with dexamethasone (DXM) during the synthesis, named PPA@DXM and P(PA-co-AA)@DXM, were prepared by a modified surfactant free emulsion method. The loading was studied as a function of different functionality grades of the copolymer and different amounts of drug, obtaining up to 90% of drug loading for P(PA-co-AA)@DXM with 8\\\/1 PA\\\/AA monomer ratio. The SEM images and DLS measurements showed spheres with average diameters in the range 190-500 nm, depending on the content of acrylic acid monomer units in the copolymer and of DXM loading. ζ-potential and surface charge density of DXM loaded nanoparticles were also investigated and confirm the charge density modulation in the range 0.62-2.68σ (μC\\\/m(2)). The results highlight the enhanced capability of our copolymer of hosting DXM, with the advantage of a control of size, surface functionality, charge and release. Moreover we demonstrate for the first time the ability of P(PA-co-AA) DXM loaded nanoparticles to be used in the apoptosis inhibition of human tumor cells (HeLa). On the basis of the results obtained by comparing the effects elicited in HeLa cells by free DXM versus DXM loaded nanoparticles we confirmed the biological efficacy of our preparation.. . ""

Humidity sensors based on nanobeads of conjugated polymers, i.e., polyphenylacetylene (PPA) and poly[phenylacetylene-(co-2-hydroxyethyl methacrylate] P(PAMEMA), prepared by modified emulsion polymerization technique, have been developed using resistive type and quartz crystal microbalance (QCM) devices. The investigations on the electrical response of PPA and P(PA/HEMA) nanobeads were performed and resistive humidity sensors based on ordered arrays of these nanostructured polymeric materials showed fast and reproducible current intensity variations in the range of relative humidity RH 5-90%. Polymeric nanostructured films deposited on the quartz electrode of QCM showed a linear sensitivity of 0.024 Hz/ppmv and short response time. Copyright © 2007 American Scientific Publishers All rights reserved.

Incorporation of nanoparticles composed of surface-functionalized fumed silica (FS) or native colloidal silica (CS) into a nanostructured block copolymer yields hybrid nanocomposites whose mechanical properties can be tuned by nanoparticle concentration and surface chemistry. In this work, dynamic rheology is used to probe the frequency and thermal responses of nanocomposites composed of a symmetric poly(styrene-b-methyl methacrylate) (SM) diblock copolymer and varying in nanoparticle concentration and surface functionality. At sufficiently high loading levels, FS nanoparticle aggregates establish a load-bearing colloidal network within the copolymer matrix. Transmission electron microscopy images reveal the morphological characteristics of the nanocomposites under these conditions.