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The crystallization behavior of propene–ethylene (iPPC2), propene–butene (iPPC4), propene–pentene (iPPC5), and propene–hexene (iPPC6) isotactic copolymers, prepared with single center metallocene catalysis, is described. Thanks to the perfectly random distribution of comonomers along the macromolecules, these copolymers can be considered as model for the crystallization behavior of isotactic polypropylene (iPP) that is mainly defined by the average length of the regular propene sequences. A model of the crystallization behavior of iPP is described based on the definition of a double effect of defects (stereodefects and comonomers), the interruption effect of defects excluded from the crystals that shortens the length of the crystallizable propene sequences inducing crystallization of the γ form, and the effect of inclusion of defects in the crystals of α form, γ form or δ form that induces the crystallization of the form whose lattice is less disturbed by the defect. [ABSTRACT FROM AUTHOR]

It is still problematic to define a direct relationship between specific properties of a nanostructured surface (e.g., wettability) and its morphology. Not surprisingly, scientists continue to explore en masse the cut‐and‐try method. In this work, new insights are presented into the correlation of functional properties of the complex nanocomposites with their morphological characteristics. Using polyethylene‐terephthalate (PET) as a model material due to its importance and wide use in experiments, super‐hydrophilic nanocomposites amenable to be used in a variety of industrial applications are first developed, by exposing PET samples to oxygen plasma under controlled conditions. The morphology of the surfaces is confirmed using AFM and SEM techniques, and wettability in air and its oleophobic properties in water using contact angle and roll‐off measurements. Next, different analytical tools such as Minkowski connectivity (Euler‐Poincaré characteristic), Hough distributions and 2D FFT are applied to study ordering, connectivity, and fractal characteristics of the samples. It is concluded that fractal dimension, along with ordering and connectivity, are among the major characteristics of the nanocomposite that determine many important physical and chemical properties of the functional nanomaterials, and the fractal dimension could be a target morphological feature to inform the design of fabrication technology. [ABSTRACT FROM AUTHOR]

Artificial metalloenzymes as catalysts are promising candidates for their use in different technologies, such as bioremediation, biomass transformation, or biosensing. Despite this, their practical exploitation is still at an early stage. Immobilized natural enzymes have been proposed to enhance their applicability. Immobilization may offer several advantages: (i) catalyst reuse; (ii) easy separation of the enzyme from the reaction medium; (iii) better tolerance to harsh temperature and pH conditions. Here, we report an easy immobilization procedure of an artificial peroxidase on different surfaces, by means of click chemistry. FeMC6*a, a recently developed peroxidase mimic, has been functionalized with a pegylated aza‐dibenzocyclooctyne to afford a "clickable" biocatalyst, namely FeMC6*a‐PEG4@DBCO, which easily reacts with azide‐functionalized molecules and/or nanomaterials to afford functional bioconjugates. The clicked biocatalyst retains its structural and, to some extent, its functional behaviors, thus housing high potential for biotechnological applications. [ABSTRACT FROM AUTHOR]

The adsorption of myoglobin (Mb) onto nanoporous thin films build up using block‐copolymers (BCPs) is analyzed. The nanoporous thin films, fabricated by exploiting self‐assembly of lamellar BCPs and the concept of sacrificial block, are characterized by a well‐defined morphology containing nanochannels of width ≈20 nm delimited by polystyrene (PS) domains, decorated with pendant poly(ethylene oxide) (PEO) chains. The adsorption of Mb onto the nanoporous material is studied by means of UV–visible spectroscopy, quartz crystal microbalance, and neutron reflectometry measurements. In order to determine the role of nanopores, experiments are also conducted by using supports made of nonporous PS thin films and nude glass slides. The results indicate that the BCP‐nanoporous material exhibits a remarkably higher adsorption capability than PS and glass. As PEO exhibits a low degree of protein adsorption, this result may be essentially attributed to the presence of the nanopores. The large surface area, the opened pore structure, and the trapping effect of the pores are the main factors determining the increased Mb adsorption capability of the BCP‐based support. Yet, the presence of PEO chains decorating the PS walls at porous surface does not prevent Mb biomolecules to establish good interactions with the support. [ABSTRACT FROM AUTHOR]

About 90% of congenital central hypoventilation syndrome (CCHS) patients show polyalanine triplet expansions in the coding region of transcription factor PHOX2B, which renders this protein an intriguing target to understand the insurgence of this syndrome and for the design of a novel therapeutical approach. Consistently with the role of PHOX2B as a transcriptional regulator, it is reasonable that a general transcriptional dysregulation caused by the polyalanine expansion might represent an important mechanism underlying CCHS pathogenesis. Therefore, this study focused on the biochemical characterization of different PHOX2B variants, such as a variant containing the correct C‐terminal (20 alanines) stretch, one of the most frequent polyalanine expansions (+7 alanines), and a variant lacking the complete alanine stretch (0 alanines). Comparison of the different variants by a multidisciplinary approach based on different methodologies (including circular dichroism, spectrofluorimetry, light scattering, and Atomic Force Microscopy studies) highlighted the propensity to aggregate for the PHOX2B variant containing the polyalanine expansion (+7‐alanines), especially in the presence of DNA, while the 0‐alanines variant resembled the protein with the correct polyalanine length. Moreover, and unexpectedly, the formation of fibrils was revealed only for the pathological variant, suggesting a plausible role of such fibrils in the insurgence of CCHS. [ABSTRACT FROM AUTHOR]

Block-copolymers (BCPs) self-assembling provides a unique tool for realizing large-area ordered metamaterials with desired optical properties due to the rich range of tunable nano-morphologies and to the chemical properties of the block polymers that can lead to the selective inclusion of functionalized nanoparticles (NPs) in specific nanodomains, generating periodic arrays of NPs according to the geometry of the BCP acting as template. In this work, we investigate nanostructured thin films of polystyrene- block-poly(methylmethacrylate) (PS-PMMA) BCP filled with functionalized metallic (Au) nanoparticles. The BCP is characterized by an hexagonal array of PS cylinders in the PMMA matrix and the Au NPs are selectively included in the PS cylindrical domains. The optical properties of such nano-structures are strongly affected by localized surface plasmons (LSPs) in the NPs. We theoretically demonstrate that the optical properties of such nano-structures can be tuned by varying the NPs loading concentration and the NPs radius. Then, we investigate the effects of the hexagonal geometry on the collective plasmonic oscillations. We fabricated the PS-PMMA/Au NPs composite and we experimentally demonstrate the existence of collective plasmonic resonances of gold nanoparticles after an electromagnetic stimulation, arising from the ordered arrangement of AuNPs in the periodic array of hexagonally packed cylinders created by BCP self-assembly. This approach allows a fine modulation of the NPs optical properties and can be used as an intriguing and versatile tool to build useful devices for Optics & Photonics applications, with significant benefits for both fundamental and applied investigations. [ABSTRACT FROM AUTHOR]

We report the cocrystallization of the regio- and stereoregular chiral copolymer poly(limonene carbonate). To the best of our knowledge, this marks the first example of an amorphous, enantiomerically pure polymer that becomes crystalline upon stereocomplexation with its complementary enantiomer. By analyzing X-ray powder diffraction data, we propose a packing model in which sheets of enantiopure chains interdigitate with layers of the opposite enantiomer, forming a 'steric zipper'. [ABSTRACT FROM AUTHOR]

A strategy to tailor the properties of isotactic polypropylene, based on the combination of the crystallization of the mesophase and the control of the molecular structure and concentration of stereodefects via polymerization with metallocene catalysts, is presented. The mechanical properties can be modulated through the conventional slow crystallization from the melt in the α and γ forms, depending on the concentration of stereodefects, or the crystallization of the mesophase by melt quenching. The most stereoirregular sample with rr concentration of 11% shows elastic behavior either when it is slowly crystallized in the γ form or when it is crystallized in the mesomorphic form, but with remarkable differences in the values of the modulus and tensile strength. [ABSTRACT FROM AUTHOR]

The crystal structure of syndiotactic polystyrene (sPS) co-crystals of δ-class is discussed with the aim of identifying molecular descriptors that allow predicting the lattice distortions induced by the inclusion of guest molecules inside the cavities of the nanoporous δ-form. Based on the consideration that monoclinic and triclinic clathrates and intercalates of sPS form as a result of the unique deformability of the cavities of the δ-form, the identified parameters are the fractional occupancy factors of the undeformed cavity of the δ-form from guests along the a-axis, the c-axis, and the normal to the (010) planes of the crystals, and the relative orientation of the guests to the chain axes. [ABSTRACT FROM AUTHOR]