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9 pags., 9 figs., 2 tabs., Infrared spectroscopy (IR) and Broadband Dielectric Spectroscopy (BDS) experiments have been performed in poly(trimethylene 2,5-furanoate)(PTF) and poly(trimethylene terephthalate)(PTT) below their glass transition temperatures. The BDS experiments reveal a richer inter-molecular dynamic for PTT as characterized by a multimodal β relaxation in contrast with the monomodal one exhibited by PTF. The evolution with temperature of comparable IR absorption bands is very similar for PTF and PTT and shows small shifts in wavenumbers towards lower values, with exception of the band related to the stretching mode of the carbonyl group. In addition, a significant difference appears in the shape of the bands associated with the –C[dbnd]O stretching. While for PTT the absorption feature is comprised of a single component, that for PTF exhibits several components suggesting the presence of hydrogen bonds. This effect may be responsible for the monomodal shape of the β relaxation of PTF since a higher degree of intramolecular coupling between the furan ring and the rest of the monomer is expected. Density Functional Theory (DFT) calculations support the experimental results revealing that as temperature increases an increment of the syn conformations of the 2,5-furandicarboxylic acid (FDCA) moiety is likely to occur in the amorphous state. The energy gain from more stable anti to less stable syn isomers can be compensated by the formation of hydrogen bonds between interchain FDCA moieties in syn conformations. This effect may cause additional hindrance to the intermolecular dynamics of the dielectric β relaxation. It is conceivable that the hindrance exhibited by PTF in both intra and inter-molecular dynamics may play a role in the reduction of gas diffusion and permeability of PTF in comparison with PTT., Grants PID2019-107514 GB-I00/AEI/10.13039/501100011033 and PID2019-106125 GB-I00/AEI/10.13039/501100011033 funded by MCIN/AEI/10.13039/501100011033 and by “ ERDF A way of making Europe”. GS acknowledges grant RYC2020-029810-I funded by MCIN/ AEI/10.13039/501100011033 and by “ ESF Investing in your future”. SP would like to thank for financial support from the National Science Centre within project SONATA no 2018/31/D/ST8/00792. A

9 pags., 6 figs., Evolved stars are foundries of chemical complexity, gas and dust that provide the building blocks of planets and life, and dust nucleation first occurs in their photosphere. The circumstellar regions enveloping these stars, despite their importance, remain hidden to many observations, and dust formation processes are therefore still poorly understood. Laboratory astrophysics provides complementary routes to unveil these chemical processes, but most experiments rely on combustion or plasma decomposition of molecular precursors under physical conditions far removed from those in space. To reproduce and characterize the bottom-up dust formation process, we have built an ultra-high vacuum machine combining atomic gas aggregation with advanced in situ characterization techniques. We show that carbonaceous dust analogues that formed from low-pressure gas-phase condensation of carbon atoms in a hydrogen atmosphere, in a ratio of carbon to molecular hydrogen similar to that reported for evolved stars, lead to the formation of amorphous carbon nanograins and aliphatic carbon clusters. Aromatic species and fullerenes do not form effectively under these conditions, raising implications for a revision of the chemical mechanisms taking place in circumstellar envelopes., We thank the European Research Council for funding support under Synergy Grant ERC-2013-SyG, G.A. 610256 (NANOCOSMOS). We also acknowledge partial support from the Spanish Research Agency (AEI) through grants MAT2017-85089-c2-1R, FIS2016-77578-R and FIS2016-77726-C3-1-P. Support from the FotoArt-CM Project (P2018/NMT-4367) through the Program of R&D activities between research groups in Technologies 2013, cofinanced by European Structural Funds, is also recognized.

IOP Publishing [Society Publisher] Silicon is present in interstellar dust grains, meteorites and asteroids, and to date 13 silicon-bearing molecules have been detected in the gas phase toward late-type stars or molecular clouds, including silane and silane derivatives. In this work, we have experimentally studied the interaction between atomic silicon and hydrogen under physical conditions mimicking those in the atmosphere of evolved stars. We have found that the chemistry of Si, H, and H2 efficiently produces silane (SiH4), disilane (Si2H6) and amorphous hydrogenated silicon (a-Si:H) grains. Silane has been definitely detected toward the carbon-rich star IRC +10216, while disilane has not been detected in space yet. Thus, based on our results, we propose that gas-phase reactions of atomic Si with H and H2 are a plausible source of silane in C-rich asymptotic giant branch stars, although its contribution to the total SiH4 abundance may be low in comparison with the suggested formation route by catalytic reactions on the surface of dust grains. In addition, the produced a-Si:H dust analogs decompose into SiH4 and Si2H6 at temperatures above 500 K, suggesting an additional mechanism of formation of these species in envelopes around evolved stars. We have also found that the exposure of these dust analogs to water vapor leads to the incorporation of oxygen into Si–O–Si and Si–OH groups at the expense of SiH moieties, which implies that if this kind of grain is present in the interstellar medium, it will probably be processed into silicates through the interaction with water ices covering the surface of dust grains. We thank the European Research Council for funding support under Synergy grant ERC-2013-SyG, G.A. 610256 (NANOCOSMOS). Also, we acknowledge partial support from the Spanish MINECO through grants MAT2017-85089-c2-1R, FIS2016-77726-C3-1-P, FIS2016-77578-R, AYA2016-75066-C2-1-P and RyC-2014-16277. Support from the FotoArt-CM Project (P2018/NMT 4367) through the Program of R&D activities between research groups in Technologies 2013, cofinanced by European Structural Funds, is also acknowledged. G.T.C. acknowledges funding from the Comunidad Autonoma de Madrid (PEJD-2018-PRE/IND-9029). Peerreview

Titanium-carbide molecular clusters are thought to form in the circumstellar envelopes (CSEs) of carbon-rich Asymptotic Giant Branch stars (AGBs) but, to date, their detection has remained elusive. To facilitate the astrophysical identification of those clusters in AGBs and post-AGBs environments, the molecular structures and optical absorption spectra of small Ti$_n$C$_x$ clusters, with n = 1-4 and x = 1-4, and some selected larger clusters, Ti$_3$C$_8$, Ti$_4$C$_8$, Ti$_6$C$_{13}$, Ti$_7$C$_{13}$, Ti$_8$C$_{12}$, Ti$_9$C$_{15}$, and Ti$_{13}$C$_{22}$, have been calculated. The density functional formalism, within the B3LYP approximation for electronic exchange and correlation, was used to find the lowest energy structures. Except the clusters having a single Ti atom, the rest exhibit three-dimensional structures. Those are formed by a Ti fragment surrounded in general by carbon dimers. The optical spectra of Ti$_n$C$_x$, computed by time-dependent density functional theory, using the corrected CAM-B3LYP functional, show absorption features in the visible and near infrared regions which may help in the identification of these clusters in space. In addition, most of the clusters have sizable electric dipole moments, allowing their detection by radioastronomical observations.

8 pags, 4 figs. -- The online version contains supplementary material available at https://doi.org/10.1038/s41467-021-26184-0, Development of sustainable processes for hydrocarbons synthesis is a fundamental challenge in chemistry since these are of unquestionable importance for the production of many essential synthetic chemicals, materials and carbon-based fuels. Current industrial processes rely on non-abundant metal catalysts, temperatures of hundreds of Celsius and pressures of tens of bars. We propose an alternative gas phase process under mild reaction conditions using only atomic carbon, molecular hydrogen and an inert carrier gas. We demonstrate that the presence of CH2 and H radicals leads to efficient C-C chain growth, producing micron-length fibres of unbranched alkanes with an average length distribution between C23-C33. Ab-initio calculations uncover a thermodynamically favourable methylene coupling process on the surface of carbonaceous nanoparticles, which is kinematically facilitated by a trap-and-release mechanism of the reactants and nanoparticles that is confirmed by a steady incompressible flow simulation. This work could lead to future alternative sustainable synthetic routes to critical alkane-based chemicals or fuels., We thank Jose Criado for the artwork schematics of the system, in figures 4 and S1; Funding: We thank the European Research Council for funding support under Synergy grant ERC-2013-SyG, G.A. 610256 (NANOCOSMOS). Also, we acknowledge partial support from the Spanish MINECO through grants PID2020-113142RB-C21, PID2019106315RB-I00, and PID2019-106315RB-I00, EU ERC CoG HyMAP 648319, and from the regional government through project S2018-NMT-4367 (FotoArt-CM). AM acknowledges to the Spanish Ministry of Science (RYC2018-024561-I), to the Regional Government of Aragon (DGA E13_20R), to the National Natural Science Foundation of China (NFSC-21850410448, NSFC-21835002), and to the The Centre for Highresolution Electron Microscopy (ChEM), supported by SPST of ShanghaiTech University under contract No. EM02161943. S.K. and G.H. acknowledge funding from the Turbulent Superstructures Program of the German National Science Foundation (DFG)

Interstellar carbonaceous dust is mainly formed in the innermost regions of circumstellar envelopes around carbon-rich asymptotic giant branch (AGB) stars. In these highly chemically stratified regions, atomic and diatomic carbon, along with acetylene are the most abundant species after H(2) and CO. In a previous study, we addressed the chemistry of carbon (C and C(2)) with H(2) showing that acetylene and aliphatic species form efficiently in the dust formation region of carbon-rich AGBs whereas aromatics do not. Still, acetylene is known to be a key ingredient in the formation of linear polyacetylenic chains, benzene and polycyclic aromatic hydrocarbons (PAHs), as shown by previous experiments. However, these experiments have not considered the chemistry of carbon (C and C(2)) with C(2)H(2). In this work, by employing a sufficient amount of acetylene, we investigate its gas-phase interaction with atomic and diatomic carbon. We show that the chemistry involved produces linear polyacetylenic chains, benzene and other PAHs, which are observed with high abundances in the early evolutionary phase of planetary nebulae. More importantly, we have found a non-negligible amount of pure and hydrogenated carbon clusters as well as aromatics with aliphatic substitutions, both being a direct consequence of the addition of atomic carbon. The incorporation of alkyl substituents into aromatics can be rationalized by a mechanism involving hydrogen abstraction followed by methyl addition. All the species detected in gas phase are incorporated into the nanometric sized dust analogues, which consist of a complex mixture of sp, sp(2) and sp(3) hydrocarbons with amorphous morphology.

We present a new protocol to grow large-area, high-quality single-layer graphene on Cu foils at relatively low temperatures. We use C60 molecules evaporated in ultra high vacuum conditions as carbon source. This clean environment results in a strong reduction of oxygen-containing groups as depicted by X-ray photoelectron spectroscopy (XPS). Unzipping of C60 is thermally promoted by annealing the substrate at 800 °C during evaporation. The graphene layer extends over areas larger than the Cu crystallite size, although it is changing its orientation with respect to the surface in the wrinkles and grain boundaries, producing a modulated ring in the low energy electron diffraction (LEED) pattern. This protocol is a self-limiting process leading exclusively to one single graphene layer. Raman spectroscopy confirms the high quality of the grown graphene. This layer exhibits an unperturbed Dirac-cone with a clear n-doping of 0.77 eV, which is caused by the interaction between graphene and substrate. Density functional theory (DFT) calculations show that this interaction can be induced by a coupling between graphene and substrate at specific points of the structure leading to a local sp3 configuration, which also contribute to the D-band in the Raman spectra., Financial support from EU Horizon 2020 research and innovation program under grant agreement No. 696656 (GrapheneCore1-Graphene-based disruptive technologies) and Spanish MINECO (grants MAT2014-54231-C4-1-P,MAT2014-52405-C2-2-R, CSD2009-00013, MAT2015-64110) is acknowledged. JA and NR are supported by the FPI program from MINECO (BES-2012-058600 and BES-2015-072642, respectively). CM and JIM acknowledge the financial support by the “Ramón y Cajal” Program of MINECO (RYC-2014-16626 and RYC-2015-17730, respectively). JIM and GS acknowledge funding from the ERC-Synergy Program (grant ERC-2013-SYG-610256 Nanocosmos). JIM thanks CTI-CSIC for use of computing resources. MK and VV acknowledge funding from ERC-CZ (LL1301) project. GO-I acknowledges FCT for his grant (SFRH/BPD/90562/2012).

12 pags., 8 figs., 1 tab., Laboratory astrochemistry aims at simulating, in the laboratory, some of the chemical and physical processes that operate in different regions of the universe. Amongst the diverse astrochemical problems that can be addressed in the laboratory, the evolution of cosmic dust grains in different regions of the interstellar medium (ISM) and its role in the formation of new chemical species through catalytic processes present significant interest. In particular, the dark clouds of the ISM dust grains are coated by icy mantles and it is thought that the ice–dust interaction plays a crucial role in the development of the chemical complexity observed in space. Here, we present a new ultra-high vacuum experimental station devoted to simulating the complex conditions of the coldest regions of the ISM. The INFRA-ICE machine can be operated as a standing alone setup or incorporated in a larger experimental station called Stardust, which is dedicated to simulate the formation of cosmic dust in evolved stars. As such, INFRA-ICE expands the capabilities of Stardust allowing the simulation of the complete journey of cosmic dust in space, from its formation in asymptotic giant branch stars to its processing and interaction with icy mantles in molecular clouds. To demonstrate some of the capabilities of INFRA-ICE, we present selected results on the ultraviolet photochemistry of undecane (C11H24) at 14 K. Aliphatics are part of the carbonaceous cosmic dust, and recently, aliphatics and short n-alkanes have been detected in situ in the comet 67P/Churyumov–Gerasimenko., We thank the European Research Council for funding support under Synergy Grant No. ERC-2013-SyG, G.A. 610256 (NANOCOSMOS). In addition, partial support from the Spanish Research Agency (AEI) through Grant Nos. MAT2017-85089- c2-1R and FIS2016-77578-R is acknowledged. Support from the FotoArt-CM Project (No. P2018/NMT 4367) through the Program of R&D activities between research groups in Technologies 2013, co-financed by European Structural Funds, is also acknowledged. G.T.-C. acknowledges funding from the Comunidad Autónoma de Madrid (Grant No. PEJD-2018-PRE/IND-9029).

13 pags., 12 figs., 2 tabs., Interstellar carbonaceous dust is mainly formed in the innermost regions of circumstellar envelopes around carbon-rich asymptotic giant branch stars (AGBs). In these highly chemically stratified regions, atomic and diatomic carbon, along with acetylene, are the most abundant species after H and CO. In a previous study, we addressed the chemistry of carbon (C and C) with H showing that acetylene and aliphatic species form efficiently in the dust formation region of carbon-rich AGBs whereas aromatics do not. Still, acetylene is known to be a key ingredient in the formation of linear polyacetylenic chains, benzene, and polycyclic aromatic hydrocarbons (PAHs), as shown by previous experiments. However, these experiments have not considered the chemistry of carbon (C and C) with CH. In this work, by employing a sufficient amount of acetylene, we investigate its gas-phase interaction with atomic and diatomic carbon. We show that the chemistry involved produces linear polyacetylenic chains, benzene, and other PAHs, which are observed with high abundances in the early evolutionary phase of planetary nebulae. More importantly, we have found a nonnegligible amount of pure and hydrogenated carbon clusters as well as aromatics with aliphatic substitutions, both being a direct consequence of the addition of atomic carbon. The incorporation of alkyl substituents into aromatics can be rationalized by a mechanism involving hydrogen abstraction followed by methyl addition. All the species detected in the gas phase are incorporated into nanometric-sized dust analogs, which consist of a complex mixture of sp, sp, and sp hydrocarbons with amorphous morphology., We thank the European Research Council for funding support under Synergy grant ERC-2013-SyG, G.A. 610256 (NANOCOSMOS). Also, partial support from the Spanish Research Agency (AEI) through grants MAT2017-85089-c2- 1R, FIS2016-77578-R, FIS2016-77726-C3-1-P, AYA2016- 75066-C2-1-P, and RyC-2014-16277 is acknowledged. Support from the FotoArt-CM Project (P2018/NMT 4367) through the Program of R&D activities between research groups in Technologies 2013, co-financed by European Structural Funds, is also acknowledged. G.TC. acknowledges funding from the Comunidad Autónoma de Madrid (PEJD-2018-PRE/ IND-9029)

13 pags., 8 figs. -- Open Access funded by Creative Commons Atribution Licence 4.0, The increasing demand for nanostructured materials is mainly motivated by their key role in a wide variety of technologically relevant fields such as biomedicine, green sustainable energy or catalysis. We have succeeded to scale-up a type of gas aggregation source, called a multiple ion cluster source, for the generation of complex, ultra-pure nanoparticles made of different materials. The high production rates achieved (tens of g/day) for this kind of gas aggregation sources, and the inherent ability to control the structure of the nanoparticles in a controlled environment, make this equipment appealing for industrial purposes, a highly coveted aspect since the introduction of this type of sources. Furthermore, our innovative UHV experimental station also includes in-flight manipulation and processing capabilities by annealing, acceleration, or interaction with background gases along with in-situ characterization of the clusters and nanoparticles fabricated. As an example to demonstrate some of the capabilities of this new equipment, herein we present the fabrication of copper nanoparticles and their processing, including the controlled oxidation (from Cu to CuO through CuO, and their mixtures) at different stages in the machine., This work was supported by the European Union [grant number ERC-2013-SyG 610256 NANOCOSMOS]; the Spanish MINECO [grant numbers MAT2017-85089-C2-1-R, MAT2014-54231-C4-1-P, MAT2014-54231- C4-4-P, MAT2014-59772-C2-2-P, FIS2016-77578-R, FIS2013-48087-C2-1P, FIS2016-77726-C3-1P and CSIC13-4E-1775].

Spray coating, a simple and low‐cost technique for large‐scale film deposition, is employed to fabricate mesoporous titania films, which are electron‐transporting layers in all‐solid‐state dye‐sensitized solar cells (DSSCs). To optimize solar cell performance, presynthesized crystalline titania nanoparticles are introduced into the mesoporous titania films. The composite film morphology is examined with scanning electron microscopy, grazing incidence small‐angle X‐ray scattering, and nitrogen adsorption–desorption isotherms. The crystal phase and crystallite sizes are verified by X‐ray diffraction measurements. The photovoltaic performance of all‐solid‐state DSSCs is investigated. The findings reveal that an optimal active layer of the all‐solid‐state DSSC is obtained by including 50 wt% titania nanoparticles, showing a foam‐like morphology with an average pore size of 20 nm, featuring an anatase phase, and presenting a surface area of 225.2 m2 g−1. The optimized morphology obtained by adding 50 wt% presynthesized crystalline titania nanoparticles yields, correspondingly, the best solar cell efficiency of 2.7 ± 0.1%., Financial support by TUM.solar in the context of the Bavarian Collaborative Research Project “Solar Technologies Go Hybrid” (SolTech), by the GreenTech Initiative (Interface Science for Photovoltaics – ISPV) of the EuroTech Universities and by the Nanosystems Initiative Munich (NIM) is gratefully acknowledged. V.K. thanks the Bavarian State Ministry of Sciences, Research and Arts for funding this research work via project “Energy Valley Bavaria.” L.S., W.W., and Y.Y. acknowledge the China Scholarship Council (CSC).

A subsea flexible pipe containing isotropic poly(vinylidene fluoride) (PVDF) layers is subjected to rapid decompression after being put in pressurized equilibrium with a fluid containing supercritical CO2. The PVDF layers have flowed radially into gaps of adjacent metallic coils forming whitened noses. Microbeam small-angle X-Ray scattering (SAXS) scanning reveals a considerable morphological gradient in the polymer layers. PVDF layers (inner: wear, outer: barrier) in two zones (undamaged and damaged) are scanned. Far from noses and damage zone, the samples are isotropic without voids. Their morphological parameters are determined and compared to virgin material. Approaching the noses, the structure turns into highly oriented microfibrils perpendicular to the local flow into the gaps. Here, voids extend parallel to the microfibrils. At edges of the metallic structure, they turn more perpendicular to the layer. Crystallite orientation extends out to both sides of the whitened nose regions, but in the undamaged samples, tilting of the orientation direction and void-formation are restricted to the white regions: successive mechanisms of cold drawing are mapped into space. Under the damaged spot, voids and crystallite orientation extend through the entire layer. POLYM. ENG. SCI., 2015. © 2015 Society of Plastics Engineers

The structure and magnetic behavior of hybrid films composed of maghemite (-Fe2O3) nanoparticles (NPs) and an asymmetric diblock copolymer (DBC) polystyrene61-block-polyN-isopropylacrylamide115 are investigated. The NPs are coated with PS chains, which allow for a selective incorporation inside the PS domains at different NP concentrations. Upon incorporation of low amounts of NPs into the DBC thin films, the initial parallel (to film surface) cylinder morphology changes to a well ordered, perpendicularly oriented one. The characteristic domain distance of the DBC is increased due to the swelling of the PS domains with NPs. At higher NP concentrations, the excess NPs which can no longer be embedded in the PS domains, are accumulated at the film surface, and NP aggregates form. Irrespective of NP concentration, a superparamagnetic behavior of the metal oxide-DBC hybrid films is found. Such superparamagnetic properties make the established hybrid films interesting for high density magnetic storage media and thermoresponsive magnetic sensors., This work was supported by the BMBF (German Ministry of Research and Education) Grant No. 03DU03MU and by the Nanosystems Initiative Munich (NIM). Y.Y. and B.S. acknowledge the China Scholarship Council (CSC). V.K. thanks the Bavarian State Ministry of Education, Science and the Arts for funding this research work via project “Energy Valley Bavaria”.

One of the major problems in the confectionery industry is chocolate fat blooming, that is, the formation of white defects on the chocolate surface due to fat crystals. Nevertheless, the mechanism responsible for the formation of chocolate fat blooming is not fully understood yet. Chocolate blooming is often related to the migration of lipids to the surface followed by subsequent recrystallization. Here, the migration pathway of oil into a cocoa butter matrix with different dispersed particles was investigated by employing microfocus small-angle X-ray scattering and contact angle measurements. Our results showed that the chocolate powders get wet by the oil during the migration process and that the oil is migrating into the pores within seconds. Subsequently, cocoa butter is dissolved by the oil, and thus, its characteristic crystalline structure is lost. The chemical process provoked by the dissolution is also reflected by microscopical changes of the surface morphology of chocolate model samples after several hours from the addition of oil to the sample. Finally, the surface morphology was investigated before and after oil droplet exposure and compared to that of water exposure, whereby water seems to physically migrate through the particles, namely cocoa powder, sucrose, and milk powder, which dissolve in the presence of water.

The progress of organic electronics demands an increased participation of nanotechnology, and it has already been shown that the presence of metallic nanoparticles and/or nanostructured thin films can enhance the device performance. Nevertheless, to gain control over the device final performance, it is crucial to achieve a profound understanding of the nanostructure development and assembly. We investigate the growth kinetics of silver (Ag) on a tris(8-hydroxyquinolinato)aluminum (Alq3) thin film via sputter deposition. The increase of the average electron density of the Ag nanostructured film is observed to follow a sigmoidal shape development as a function of the deposited Ag thickness, as a consequence of dominant island-mediated growth. The nanoclustered film is percolated at around a thickness of 5.0 ± 0.1 nm. At this film thickness the effective film density is about 50%. Moreover, our simulation results indicate that the shape of the nanoclusters changes from truncated spheres to cylinders upon sur...

Crazes constitute one of the most common failure mechanisms in polymers. They act as fracture precursors, severely degrading the mechanical properties of the material. Thus, a deep understanding of the chain rearrangement occurring inside crazes is of utmost fundamental and practical importance. We have employed synchrotron infrared microspectroscopy (SIRMS) and Raman microspectroscopy to investigate the conformational changes inside micron-sized crazes in poly(ethylene terephthalate), PET. A promotion of the full-extended chain conformational structure at the expense of mainly the trans amorphous mesomorphic phase along with an increase in crystallinity of around 4% has been found. These results differ from what we observed across the deformation neck during PET cold drawing, where no promotion of the all-trans crystalline conformation occurred for slow drawing speeds at temperatures well below the glass transition. Our results show the tremendous capabilities of advanced vibrational microspectroscopy techniques to investigate microscale phenomena in polymer science.

I. Tanarro et al. -- 16 pags., 18 figs., app., We present a proof of concept on the coupling of radio astronomical receivers and spectrometers with chemical reactors and the performances of the resulting setup for spectroscopy and chemical simulations in laboratory astrophysics. Several experiments including cold plasma generation and UV photochemistry were performed in a 40 cm long gas cell placed in the beam path of the Aries 40 m radio telescope receivers operating in the 41–49 GHz frequency range interfaced with fast Fourier transform spectrometers providing 2 GHz bandwidth and 38 kHz resolution. The impedance matching of the cell windows has been studied using di erent materials. The choice of the material and its thickness was critical to obtain a sensitivity identical to that of standard radio astronomical observations. Spectroscopic signals arising from very low partial pressures of CH3OH, CH3CH2OH, HCOOH, OCS, CS, SO2 (, The research leading to these results has received funding from the European Research Council under the European Union’s Seventh Framework Programme (FP/2007-2013)/ERC-SyG-2013 Grant Agreement No. 610256 NANOCOSMOS and from spanish MINECO CSD2009-00038 (ASTROMOL) under the Consolider-Ingenio Program. We also thank spanish MINECO for funding under grants AYA2012-32032, AYA2016-75066-C2-1-P, FIS2013-48087-C2-1-P, FIS2016-77726-C3-1-P, FIS2016-77578-R, MAT2014- 54231-C4-1-P.

Mesoporous titania is a cheap and widely used material for photovoltaic applications. To enable a large-scale fabrication and a controllable pore size, we combined a block copolymer-assisted sol–gel route with spray coating to fabricate titania films, in which the block copolymer polystyrene-block-poly(ethylene oxide) (PS-b-PEO) is used as a structure-directing template. Both the macroscale and nanoscale are studied. The kinetics and thermodynamics of the spray deposition processes are simulated on a macroscale, which shows a good agreement with the large-scale morphology of the spray-coated films obtained in practice. On the nanoscale, the structure evolution of the titania films is probed with in situ grazing incidence small-angle X-ray scattering (GISAXS) during the spray process. The changes of the PS domain size depend not only on micellization but also on solvent evaporation during the spray coating. Perovskite (CH3NH3PbI3) solar cells (PSCs) based on sprayed titania film are fabricated, which showc...

We study nucleation and multilayer growth of the perylene derivative PTCDI-C

Cosolvent addition of glycerol (G) and the use of the cosolvent ethylene glycol (EG) increase the conductivity of poly(3,4-ethylenedioxythiophene):poly(styrene-sulfonate) (PEDOT:PSS) films to values on the order of indium tin oxide conductivity. The underlying morphological changes are probed via scanning electron microscopy as well as advanced scattering techniques microfocused grazing incidence small- and wide-angle X-ray scattering. The enhancement in conductivity is ascribed to fundamental morphological changes and molecular reorientation within crystalline domains. Thereby, the conductivity enhancement is directly correlated to domain ruptures toward smaller and more densely packed PEDOT domains together with an enhanced crystallinity, the removal of PSS molecules, and moreover a reorientation of the conjugated PEDOT molecules. The latter is reported and quantified here for PEDOT:PSS films for the first time.

Microfocus X-ray scattering and micro Raman spectroscopy have been applied to study the β-transcrystalline morphology in isotactic polypropylene. The transformation from the α- to the β-form through the so-called bifurcation of growth mechanism has been investigated with high spatial resolution. We found that the mixed α-β region does not present spatial correlation along the shearing direction, implying that there is no cooperative crystallization from the different β-nucleation centres. In addition, a strong change in the lamellar orientation of the α-form thin layer that induces the growth of the β-crystallites has been observed for the first time. Finally, changes in the relative intensities of some selected Raman bands allowed the observation of the α-β transformation process at the molecular level. (© 2014 WILEY-VCH Verlag GmbH &Co. KGaA, Weinheim) In fibre-reinforced materials the interaction between the fibre and the matrix strongly affects the final properties of the material. Therefore, a detailed analysis of the interface is of utmost importance. By applying a battery of different microscopic techniques, we investigate the transcrystalline polymorphic morphology of isotactic polypropylene with unprecedented spatial resolution.

Graphical abstractDisplay Omitted Gold nanowire gratings for organic photovoltaic cells were fabricated on, within and below ITO electrodes.The nanogratings have been fabricated by e-beam lithography and nano imprint lithography.The gratings were analyzed by SEM, AFM and GISAXS measurements.The tuneability of the plasmon resonance has been shown by white light extinction spectroscopy. Organic photovoltaic devices are interesting alternatives to conventional silicon based photovoltaic cells, due to potentially lower material costs and energy consumption during the fabrication process. However, the energy conversion efficiency of organic photovoltaic cells may still be improved. One possible approach is a combination with metallic nanostructures to improve light absorption properties in the active layer. We report on the fabrication and characterization of metallic nanogratings integrated with an indium tin oxide (ITO) electrode to be combined with small-molecule organic photovoltaic cells. With respect to geometry and extinction properties gratings fabricated by two different fabrication methods, conventional electron beam lithography and nanoimprint lithography, are presented. Furthermore, gratings fabricated on top of ITO are compared to gratings integrated both below and within ITO electrodes. Fabricating structures below or within electrodes is advantageous for organic thin film techniques to avoid compromising the crystallinity of the organic thin film and short-circuiting across the thin layer.

Microfluidic processes which are accompanied with structural changes at the solid–liquid interface are monitored with in situ grazing incidence small angle X-ray scattering (GISAXS) using a micro-focused X-ray beam. Changes of the nanostructure of a film of nanospheres dispersed in a matrix of sodium alginate of algal origin and its cross-linked analogue are followed during flow of water through a microfluidic channel. The initial structural changes caused by the laminar flow in the microfluidic channel are traced and demonstrate the high sensitivity and the possibilities of the in situ GISAXS technique.

Formation of highly stable metal nanostructures in a Nafion® membrane with various aspect ratios has been of considerable research interest in recent years. However, there is a need for a proper understanding of the growth mechanism of such nanostructures in Nafion® (sometimes larger than the size of water–sulfonate ionic clusters of the membrane). In this work, the early growth kinetics of silver nanoparticles (NPs) in Nafion®-117 ion-exchange membrane during in situ L-ascorbic acid reduction of Ag+ ions by time resolved in situ small-angle X-ray scattering (SAXS) using synchrotron radiation with a time resolution of 50 ms are revealed for the first time. The SAXS analyses, corroborated by transmission electron microscopy, showed that the sizes of NPs increase rapidly together with their number density until they attain a certain size that could be accommodated in the ∼5 nm water–sulfonate ionic clusters. Further growth takes place either by self-agglomeration of the particles ejected out from the water–sulfonic acid clusters or by continuous reduction of metal ions on the existing NP surfaces (uniformly or on a specific plane) leading to formation of bigger nanostructures with various aspect ratios. The time resolved information of NP growth provides an opportunity for the controlled synthesis of metal NPs with a definite size, shape and size distribution for a specific application. The catalytic properties of Ag NPs formed in the membrane were examined using borohydride reduction of a model dye methylene blue. It was observed that smaller Ag NPs with a mean diameter ∼3 nm, confined in the hydrophilic clusters of the Nafion® matrix, have reasonably good catalytic activity and a lower lag time for the onset of reduction.

The formation of metal/organic interfaces is a complicated process involving chemical interaction, physical nucleation and diffusion, and thin film growth. It is closely related to the performance of organic electronic devices. To understand this process, we investigate the system of aluminum (Al) and tris(8-hydroxyquinolinato)aluminum (Alq3) as a model, owing to the well-known strong chemical interaction between both and their close technological relevance to organic light emitting devices. By using grazing small angle incidence X-ray scattering (GISAXS), we follow the Al thin film development on top of Alq3 during radio frequency (rf) sputter deposition in real-time and without interrupting the growth process. Three growth stages have been clearly distinguished: Al diffusion into Alq3, Al/Alq3 complex agglomeration and self-assembled Al pillar nanostructure thin film development. Thus in situ GISAXS yields the fundamental insights into the formation of the metal/organic interface for small organic semic...

We investigated the spray deposition and subsequent self-assembly during drying of a polystyrene nanoparticle dispersion with in situ grazing incidence small-angle X-ray scattering at high time resolution. During the fast deposition of the dispersion and the subsequent evaporation of the solvent, different transient stages of nanoparticle assembly can be identified. In the first stage, the solvent starts to evaporate without ordering of the nanoparticles. During the second stage, large-scale structures imposed by the breakup of the liquid film are observable. In this stage, the solvent evaporates further and nanoparticle ordering starts. In the late third drying stage, the nanoparticles self-assemble into the final layer structure.

X-ray Scattering / Ares, Alicia Esther (Editor) ; : InTech, , Chapter 2 ; ISBN: 978-953-51-2887-8 ; doi:10.5772/62609; London : InTech 29-60 (2017). doi:10.5772/64877, With the advent of third-generation synchrotron sources and the development of fast two-dimensional X-ray detectors, X-ray scattering has become an invaluable tool for in-situ time-resolved experiments. In the case of thin films, grazing incidence small angle X-ray scattering (GISAXS) constitutes a powerful technique to extract morphological information not only of the thin film surface but also of buried structures with statistical relevance. Thus, recently in-situ GISAXS experiments with subsecond time resolution have enabled investigating the self-assembly processes during vacuum deposition of metallic and organic thin films as well as the structural changes of polymer and colloidal thin films in the course of wet deposition. Moreover, processing of thin films has also been investigated in-situ employing GISAXS. In this chapter, we review the current trends of time-resolved GISAXS studies. After an introduction to the GISAXS technique, we present exemplary results of metallic and organic thin film preparation, wet deposition of polymer thin films and self-assembly of colloidal thin films, as well as examples of thin film modification in, e.g., microfluidic channels and within working devices. Finally, an overview of the future perspectives in the field is provided., Published by InTech, London

The journal of chemical physics 146(5), 052803 - (2017). doi:10.1063/1.4961460, We study nucleation and multilayer growth of the perylene derivative PTCDI-C$_8$ and find a persistent layer-by-layer growth, transformation of island shapes, and an enhancement of molecular diffusivity in upper monolayers (MLs). These findings result from the evaluation of the ML-dependent island densities, obtained by in situ real-time grazing incidence small angle X-ray scattering measurements and simultaneous X-ray growth oscillations. Complementary ex situ atomic force microscopy snapshots of different growth stages agree quantitatively with both X-ray techniques. The rate and temperature-dependent island density is analyzed using different mean-field nucleation models. Both a diffusion limited aggregation and an attachment limited aggregation model yield in the first two MLs the same critical nucleus size i, similar surface diffusion attempt frequencies in the 10$^{19}$-10$^{20}$ s$^{−1}$ range, and a decrease of the diffusion barrier E$_d$ in the 2nd ML by 140 meV., Published by American Institute of Physics, Melville, NY

The morphology and the photovoltaic characteristics of a polymer–fullerene bulk‐heterojunction solar cell processed with a processing additive are probed simultaneously. The processing additive reversibly enhances the solar cell performance which decays when the additive is lost., This work was financially supported by TUM Solar in the frame of the Bavarian Collaborative Research Project “Solar technologies go Hybrid” (SolTec), the GreenTech Initiative (Interface Science for Photovoltaics – ISPV) of the EuroTech Universities, and the Nanosystems Initiative Munich (NIM). C.J.S. thanks the Bavarian State Ministry of Sciences, Research and Arts for funding this work via the International Graduate School “Materials Science of Complex Interfaces” (CompInt) and Dr. Matthias A. Ruderer for discussion and preliminary work. C.M.P. acknowledges financial support by the “International Graduate School of Science and Engineering” (IGSSE).

Fabrication of nanoparticle arrays on a substrate is one of the most concerned aspects for manipulating assembly of nanoparticles and preparing functional nanocomposites. Here, we studied in situ the assembly kinetics of polystyrene nanocolloids by using grazing incidence small-angle X-ray scattering. The structure formation of the nanoparticle film is monitored during air-brush spraying, which provides a rapid and scalable preparation. By optimizing the substrate temperature, the dispersion of the nanocolloids can be tailored to prepare monolayer film. The success of the monolayer preparations is attributed to the fast solvent evaporation which inhibits the aggregation of the nanocolloids. The present study may open a new avenue for the manufacture-friendly preparation of well-dispersed nanoparticle thin films., S.Y. acknowledges the kind financial support from Knut and Alice Wallenberg Foundation.

A simple, easily accessible solvent-free method for the dispersion of MWCNTs into PET is proposed, based on the preparation of a microparticulate polymer/nanotube masterbatch via cryogenic impact-milling and its subsequent melt blending with the bulk polymer. Thermal and mechanical properties of nanocomposites prepared using this method were evaluated as a function of nanotube concentration. Thermal stability was improved, and superior crystallization behavior of PET in the nanocomposites was observed. Significant improvements of around 25% in tensile strength and tensile modulus of the nanocomposites was achieved using this strategy, with only 0.25 wt.-% MWCNT, compared to previous literature data where 1wt.-% MWCNT was employed.

Vulcanizates of hot and cold styrene-butadiene rubber (SBR) were prepared with five different cure systems based on sulphur, 2-mercaptobenzothiazole disulphide (MBTS) and tetramethylthiuram disulphide (TMTD). The degree of crosslinking was investigated by swelling in benzene and stress-strain analysis. Thiol-amine chemical probes were employed to determine the type of crosslinks in the sulphur vulcanizates, and their dynamic-mechanical properties and thermal stability were studied in both the raw (non-crosslinked) and crosslinked state. The butadiene microstructure and the total unsaturation were determined by Raman spectroscopy. The influence of the crosslink density and the type of crosslink formed on the measured properties is discussed.

The sorption of low-molecular penetrants by thin polymer films, as well as structural changes provoked therein, is of high relevance for many fields of application. Complex permeation, diffusion, swelling, and dissolution processes are often induced within films by solvents or gases. Here, we use a novel in situ microfluidics-grazing incidence small-angle X-ray scattering (GISAXS) setup to examine changes in film thickness and in the surface structure of a thin polymer film that sorbs a good solvent. Thus, this technique is highly complementary to the established techniques on the field of diffusion in polymers. The initial stages of water uptake and swelling are resolved for a 50 nm thin, hydrophilic poly(N-isopropylacrylamide) (PNIPAM) film, before its dissolution sets in. The initial stages of swelling are tentatively described by anomalous swelling induced by a time- and space-dependent diffusion coefficient.

In-situ scanning small-angle X-ray scattering (SAXS) experiments have been performed to probe the drying of a single suspended droplet of silica colloids. It has been demonstrated that the formation of a nanoparticle shell during drying can be confirmed just by measuring the temporal evolution of the spatial transmission profile across the drying droplet. The shrinkage of the droplet stops once the shell is formed. The temporal dependence of the shell thickness and droplet radius has been estimated by quantitative analysis of the functionality of the transmission profiles. It is revealed that the position of the correlation peak originating from interactions between silica nanoparticles evolves linearly during the initial stage of drying and exhibits sigmoidal growth behavior in later stages. The interaction between colloidal particles in different drying stages has been investigated. We provide experimental confirmation of the transition from repulsive interaction to a capillary-driven short-range attraction during shell formation. The present work demonstrates that in-situ scanning SAXS on a suspended droplet is an invaluable technique for monitoring the dynamic self-organization of colloids as it probes the drying of complex fluids without the interference of a substrate.

Highly ordered block copolymer thin films have been studied extensively during the last years because they afford versatile self-assembled morphologies via a bottom-up approach. They promise to be used in applications such as polymeric membranes or templates for nanostructured materials. Among the block copolymer structures, perpendicular cylinders have received strong attention due to their ability to fabricate highly ordered nanopores and nanowires. Nanopores can be created from a thin block copolymer film upon the removal of one block by selective etching or by dissolution of one polymer block. Here we demonstrate the utilization of polystyrene-block-poly(ethylene oxide) diblock copolymer (PS-hν-PEO) with an ortho-nitrobenzyl ester (ONB) as the photocleavable block-linker to create highly ordered thin films. Removal of the PEO block by choosing an appropriate solvent upon photocleavage is expected to yield arrays of nanopores decorated with functional groups, thus lending itself to adsorption or filtration uses. While the feasibility of this approach has been demonstrated, it is crucial to understand the influence of removal conditions (i.e., efficiency of photocleavage as well as best washing solvent) and to evaluate changes in the surface topology and inner structure upon photocleavage. To this end, the time dependence evolution of the surface morphology of block copolymer thin films was studied using grazing-incidence small-angle X-ray scattering (GISAXS) technique in combination with scanning probe microscopy.

Titania nanoparticles are produced by laser ablation in liquid in order to initiate functionalization of titania with the polymer for the active layer. By combining these titania nanoparticles and water-soluble poly[3-(potassium-6-hexanoate)thiophene-2,5-diyl] (P3P6T) hybrid solar cells are realized., Financial support by TUM.solar in the frame of the Bavarian Collaborative Research Project “Solar technologies go Hybrid” (SolTec), by the GreenTech Initiative (Interface Science for Photovoltaics–ISPV) of the EuroTech Universities and by the Nanosystems Initiative Munich (NIM) is acknowledged. V.K. thanks the Bavarian State Ministry of Education, Science and the Arts for funding this research work via project “Energy Valley Bavaria”. L.S., W.W. and Y.Y. acknowledge the China Scholarship Council (CSC).

Understanding the growth of organic semi-conducting molecules with shape anisotropy is of high relevance to the processing of optoelectronic devices. This work provides insight into the growth of thin films of the prototypical rodlike organic semiconductor diindenoperylene on a microscopic level, by analyzing in detail the film morphology. We model our data, which were obtained by high-resolution grazing incidence small angle x-ray scattering (GISAXS), using a theoretical description from small angle scattering theory derived for simple liquids. Based on form factor calculations for different object types we determine how the island shapes change in the respective layers. Atomic force microscopy measurements approve our findings., 11 pages, 7 figures, accepted by Phys. Rev. B

We describe the new experimental possibilities of the micro- and nanofocus X-ray scattering beamline P03 of the synchrotron source PETRA III at DESY, Hamburg (Germany), which arise from experiments with smaller beam sizes in the micrometer range. This beamline has been upgraded recently to perform new kinds of experiments. The use of an intermediate focus allows for reducing the beam size of microfocused hard X-rays while preserving a large working distance between the focusing elements and the focus position. For the first time, this well-known methodology has been employed to grazing incidence small- and wide-angle X-ray scattering (GISAXS/GIWAXS). As examples, we highlight the applications to in situ studies using microfluidic devices in GISAXS geometry as well as the investigation of the crystallinity of thin films in GIWAXS geometry.

Colloidal particles in a tiny drying droplet are forced to assemble due to attractive capillary forces. Jamming of the particles throughout the droplet remains either isotropic or anisotropic depending upon the drying kinetics and the physicochemical environment. In this work, we explore the dynamical evolution of such an assembly process across a single evaporative droplet by in situ scanning small-angle scattering using a micro-focused X-ray beam at the synchrotron source. A methodology has been elucidated to differentiate quantitatively between the isotropic and the anisotropic jamming process. Switching of jamming behaviour depending on the initial particle volume fraction in the droplet has been demonstrated. Three distinct stages of assembly, associated with droplet shrinkage, have been revealed even during isotropic jamming. This is in contrast to the drying of a pure liquid droplet under diffusion limited evaporation. It has been established that such in situ scattering measurements can also be used to estimate the temporal evolutions of the viscosity of a drying suspension as well as the diffusivity of nanoparticles in a droplet.

Cellulose nanofibrils can be obtained from trees and have considerable potential as a building block for biobased materials. In order to achieve good properties of these materials, the nanostructure must be controlled. Here we present a process combining hydrodynamic alignment with a dispersion–gel transition that produces homogeneous and smooth filaments from a low-concentration dispersion of cellulose nanofibrils in water. The preferential fibril orientation along the filament direction can be controlled by the process parameters. The specific ultimate strength is considerably higher than previously reported filaments made of cellulose nanofibrils. The strength is even in line with the strongest cellulose pulp fibres extracted from wood with the same degree of fibril alignment. Successful nanoscale alignment before gelation demands a proper separation of the timescales involved. Somewhat surprisingly, the device must not be too small if this is to be achieved., Nanofibrils isolated from wood have potential as building blocks for materials, but in order to obtain high performance, control of the assembly process is needed. Here, the authors report a method to process nanofibrils using microfluidics, giving filaments with aligned fibrils and high strength.

The fabrication of substrates for Surface Enhanced Raman Scattering (SERS) applications matching the needs for high sensitive and reproducible sensors remains a major scientific and technological issue. We correlate the morphological parameters of silver (Ag) nanostructured thin films prepared by sputter deposition on flat silicon (Si) substrates with their SERS activity. A maximum enhancement of the SERS signal has been found at the Ag percolation threshold, leading to the detection of thiophenol, a non-resonant Raman probe, at concentrations as low as 10-10M, which corresponds to enhancement factors higher than 7 orders of magnitude. To gain full control over the developed nanostructure, we employed the combination of in-situ time-resolved microfocus Grazing Incidence Small Angle X-ray Scattering with sputter deposition. This enables to achieve a deepened understanding of the different growth regimes of Ag. Thereby an improved tailoring of the thin film nanostructure for SERS applications can be realized. © 2014 AIP Publishing LLC.

The core–shell structure in oriented cylindrical rods of polypropylene (PP) and nanoclay composites (NCs) from PP and montmorillonite (MMT) is studied by microbeam small-angle x-ray scattering (SAXS). The structure of neat PP is almost homogeneous across the rod showing regular semicrystalline stacks. In the NCs the discrete SAXS of arranged crystalline PP domains is limited to a skin zone of 300μm thickness. Even there only frozen-in primary lamellae are detected. The core of the NCs is dominated by diffuse scattering from crystalline domains placed at random. The SAXS of the MMT flakes exhibits a complex skin–core gradient. Both the direction of the symmetry axis and the apparent perfection of flake-orientation are varying. Thus there is no local fiber symmetry, and the structure gradient cannot be reconstructed from a scan across the full rod. To overcome the problem the rods are machined. Scans across the residual webs are performed. For the first time webs have been carved out in two principal directions. Comparison of the corresponding two sets of SAXS patterns demonstrates the complexity of the MMT orientation. Close to thesurface (

Over the last decade the use of synchrotron infrared microspectroscopy to spatially discriminate chemical and structural features in many different types of materials has grown considerably and has made significant impact in numerous research areas, in particular, in biological sciences and medicine. Although the brightness advantage of the synchrotron infrared (IR) source is well accepted as the key to high spatial discrimination, little attention has been given to measure the polarization properties of the synchrotron light at the sample stage in IR microscopy. In this work the intrinsic polarization of the IR source and its consequences for the study of anisotropic materials are discussed. The polarization characteristics of predominantly bending magnet radiation and predominantly edge radiation sources were measured at the microscope focus and compared. To illustrate the direct use of the intrinsic polarization of these sources in microscopy, the orientation and conformational details of a drawn polymer sample are considered.

The crystallization process of isotactic polypropylene (iPP) was studied under both dynamic and isothermal conditions for a series of multiwall carbon nanotube (MWCNT) composites with nanotube concentrations between 0.1 and 1.0% by weight. The nucleation activity of the nanofillers was confirmed for both dynamic and isothermal crystallization, and was shown to be composition dependent. The effect of the nanofiller on the crystallization of iPP was discussed using the temperature coefficients obtained to determine the interfacial free energy and free energy of nucleation. The basal interfacial free energy decreased with respect to that of neat iPP by up to 15% for as little as 0.1% MWCNT, subsequently decreasing linearly with increasing nanotube concentration. This behavior is in line with the crystallization behavior of iPP with conventional nucleating agents. POLYM. COMPOS., 2011. © 2010 Society of Plastics Engineers