Malzeme Bilimi ve Nanoteknoloji Mühendisliği Bölümü / Department of Material Science & Nanotechnology Engineering

Permanent URI for this collectionhttps://gcris3.etu.edu.tr/handle/20.500.11851/279

Browse

Now showing 1 - 20 of 100

Citation - WoS: 77
Citation - Scopus: 74
Adsorption of Habitat and Industry-Relevant Molecules on the Mosi2n4 Monolayer
(Elsevier, 2021) Bafekry, A.; Faraji, M.; Fadlallah, M. M.; Ziabari, A. Abdolahzadeh; Khatibani, A. Bagheri; Feghhi, S. A. H.; Gogova, D.
The adsorption of various environmental gas molecules, including H-2, N-2, CO, CO2, O-2, NO, NO2, SO2 H2O, H2S, NH3 and CH4, on the surface of the recently synthesized two dimensional MoSi2N4 (MSN) monolayer has been investigated by means of spin-polarized first-principles calculations. The most stable adsorption configuration, adsorption energy, and charge transfer have been computed. Due to the weak interaction between molecules studied with the MSN monolayer surface, the adsorption energy is small and does not yield any significant distortion of the MSN lattice, i.e., the interaction between the molecules and MSN monolayer surface is physisorption. We find that all molecules are physisorbed on the MSM surface with small charge transfer, acting as either charge acceptors or donors. The MSN monolayer is a semiconductor with an indirect band gap of 1.79 eV. Our theoretical estimations reveal that upon adsorption of H-2, N-2, CO, CO2, NO, H2O, H2S, NH3 and CH4 molecules, the semiconducting character of MSN monolayer is preserved and the band gap value is decreased to similar to 1.5 eV. However, the electronic properties of the MSN monolayer can be significantly altered by adsorption of O-2, NO and SO2, and a spin polarization with magnetic moments of 2, 1, 2 mu(B), respectively, can be introduced. Furthermore, we demonstrate that the band gap and the magnetic moment of adsorbed MSN monolayer can be significantly modulated by the concentration of NO and SO2 molecules. As the concentration of NO2 molecule increases, the magnetic moment increase from 1 mu(B) to 2 and 3 mu(B). In the case of the SO2 molecule with increasing of concentration, the band gap decreases from 1.2 eV to 1.1 and 0.9 eV. Obviously, our theoretical studies indicate that MSN monolayer-based sensor has a high application potential for O-2, NO, NO2 and SO2 detection.
Citation - WoS: 22
Citation - Scopus: 25
All-Dielectric Self-Cloaked Structures
(American Chemical Society, 2018-05-16) Hayran, Zeki; Kurt, Hamza; Herrero, Ramon; Botey, Muriel M.; Staliunas, Kestutis
A general procedure to design objects that are intrinsically invisible (without the necessity of an external cloak) has not been demonstrated so far. Here we propose a flexible method to design such self-cloaked objects by uncoupling the scattered waves from the incident radiation via judiciously manipulating the scattering potential of the object. We show that such a procedure is able to yield optical invisibility for any arbitrarily shaped object within any specified frequency bandwidth by simply employing isotropic nonmagnetic dielectric materials, without the usage of loss or gain material. The validity of the design principle has been verified by direct experimental observations of the spatial electric field profiles and scattering patterns at the microwave regime. Our self-cloaking strategy may have profound implications especially in noninvasive probing, cloaked sensor applications, and scattering-free non-Hermitian optics based systems. © 2018 American Chemical Society.
Citation - WoS: 3
Citation - Scopus: 4
Anomalous Single Production of the Fourth Generation Neutrino at Future Ep Colliders
(Elsevier, 2008) Çiftçi, A. K.; Çiftçi, R.; Sultansoy, Saleh
Possible single productions of the fourth standard model generation neutrino via anomalous interactions at the future ep colliders are studied. Signatures of such anomalous processes and backgrounds are discussed in detail. Discovery limits for neutrino mass and achievable values of anomalous coupling strength are determined. (c) 2008 Elsevier B.V. All rights reserved.
Citation - WoS: 12
Citation - Scopus: 15
Anomalous Single Top Production at the Lhec Based Gamma P Collider
(Elsevier, 2010) Çakır, I. T.; Çakır, O.; Sultansoy, Saleh
The top quark could provide very important information for the Standard Model extensions due to its large mass close to the electroweak symmetry breaking scale. In this work, anomalous single top production is studied by using gamma p -> W(+)b process at the LHeC based gamma p collider. The sensitivity to anomalous coupling kappa/Lambda could be reached down to 0.01 TeV-1. (c) 2010 Elsevier B.V. All rights reserved.
Citation - WoS: 50
Citation - Scopus: 51
Arrays of Aligned Supramolecular Wires by Macroscopic Orientation of Columnar Discotic Mesophases
(Amer Chemical Soc, 2012) Duran, Hatice; Hartmann, Azanza Brigitte; Steinhart, Martin; Gehrig, Dominik; Laquai, Frederic; Feng, Xinliang; Floudas, George
Structure formation, phase behavior, and dynamics of mono-bromo hexa-peri-hexabenzocoronene (HBC-Br) are strongly affected by the confinement of cylindrical nanopores with rigid walls. Using self-ordered nanoporous anodic aluminum oxide (AAO)-containing arrays of aligned nanopores with narrow size distribution as a-confining matrix, pronounced alignment of the HBC-Br columns along the nanopore axes was found to be independent of-the pore diameter. Hence, arrays of one-dimensional supramolecular HBC-Br wires with the columns uniformly oriented along the wire axes on a macroscopic:scale were. obtained, unlike with discotics bearing smaller-cores: The formation of the crystalline herringbone Structure Is shifted to lower temperatures in nanopores with diameters,cif,of a few hundred nanometers, whereas the formation of this low temperature phase is completely suppressed when the pore diameter Is below 20 lattice parameters. Moreover, the cylindrical confinement affects the disk axial dynamics-as well as the distribution of relaxation times.
Citation - WoS: 6
Citation - Scopus: 7
Catalyst Free Hydrogen Generation From Directly Disulfonated Poly (arylene Ether Sulfone) Copolymer Membranes
(Elsevier Science Bv, 2015) Sankır, Mehmet; Semiz, Levent; Demirci Sankır, Nurdan
In this study, catalyst free hydrogen generation for proton exchange membrane fuel cells (PEMFC) from directly disulfonated poly(arylene ether sulfone) copolymer membranes (BPSH) has been successfully achieved. A two-compartment reactor where an acid solution was separated horn sodium borohydride solution via a proton exchange membrane was used to evaluate hydrogen generation capacity. Hydrogen generation rate was simply controlled by tailoring the proton conductivities of the membranes. For this purposes, BPSH membranes at various percent degrees of disulfonation (25, 35 and 45 molar percent) have been prepared. The hydrogen generation performances of both BPSH and the state of art membrane, Nafion (TM) have been explored. Hydrogen generation rates were observed as 124, 175, 235 and 151.3 mL min(-1) for BPSH 25, 35, 45 and Nafion (TM), respectively. The influence of temperature on hydrogen generation rates was also investigated. it was demonstrated that the hydrogen generation performance of Nafion (TM) was deteriorated at temperatures higher than 80 degrees C due to considerable loss in its proton conductivity. Last but not least, we have demonstrated that a fuel cell has been powered along 300 h with highly stable catalyst free hydrogen generation. (C) 2015 Elsevier B.V. All rights reserved. Hydrogengeneration Protonconductivity BPSH Nafion 212
Citation - WoS: 113
Citation - Scopus: 155
Combination of Searches for Invisible Higgs Boson Decays With the Atlas Experiment
(American Physical Society, 2019) The ATLAS Collaboration; Sultansoy, Saleh
Dark matter particles, if sufficiently light, may be produced in decays of the Higgs boson. This Letter presents a statistical combination of searches for H→invisible decays where H is produced according to the standard model via vector boson fusion, Z(-)H, and W/Z(had)H, all performed with the ATLAS detector using 36.1 fb-1 of pp collisions at a center-of-mass energy of s=13 TeV at the LHC. In combination with the results at s=7 and 8 TeV, an exclusion limit on the H→invisible branching ratio of 0.26(0.17-0.05+0.07) at 95% confidence level is observed (expected). © 2019 CERN.
Citation - WoS: 121
Citation - Scopus: 201
Combination of the Searches for Pair-Produced Vectorlike Partners of the Third-Generation Quarks at S =13 Tev With the Atlas Detector
(American Physical Society, 2018-11) The ATLAS Collaboration; Sultansoy, Saleh
A combination of the searches for pair-produced vectorlike partners of the top and bottom quarks in various decay channels (T?Zt/Wb/Ht, B?Zb/Wt/Hb) is performed using 36.1 fb-1 of pp collision data at s=13 TeV with the ATLAS detector at the Large Hadron Collider. The observed data are found to be in good agreement with the standard model background prediction in all individual searches. Therefore, combined 95% confidence-level upper limits are set on the production cross section for a range of vectorlike quark scenarios, significantly improving upon the reach of the individual searches. Model-independent limits are set assuming the vectorlike quarks decay to standard model particles. A singlet T is excluded for masses below 1.31 TeV and a singlet B is excluded for masses below 1.22 TeV. Assuming a weak isospin (T,B) doublet and |VTb|â‰|VtB|, T and B masses below 1.37 TeV are excluded. © 2018 CERN. for the ATLAS Collaboration.
Citation - WoS: 1
Citation - Scopus: 1
Comment on "troublesome Aspects of the Renyi-Maxent Treatment"
(Amer Physical Soc, 2017) Oikonomou, Thomas; Bağcı, Gökhan Barış
Plastino et al. [Plastino et al., Phys. Rev. E 94, 012145 (2016)] recently stated that the Renyi entropy is not suitable for thermodynamics by using functional calculus, since it leads to anomalous results unlike the Tsallis entropy. We first show that the Tsallis entropy also leads to such anomalous behaviors if one adopts the same functional calculus approach. Second, we note that one of the Lagrange multipliers is set in an ad hoc manner in the functional calculus approach of Plastino et al. Finally, the explanation for these anomalous behaviors is provided by observing that the generalized distributions obtained by Plastino et al. do not yield the ordinary canonical partition function in the appropriate limit and therefore cannot be considered as genuine generalized distributions.
Citation - Scopus: 57
Comparison of Fragmentation Functions for Jets Dominated by Light Quarks and Gluons From Pp and Pb+pb Collisions in Atlas
(American Physical Society, 2019) The ATLAS Collaboration; Sultansoy, Saleh
Charged-particle fragmentation functions for jets azimuthally balanced by a high-transverse-momentum, prompt, isolated photon are measured in 25 pb-1 of pp and 0.49 nb-1 of Pb+Pb collision data at 5.02 TeV per nucleon pair recorded with the ATLAS detector at the Large Hadron Collider. The measurements are compared to predictions of Monte Carlo generators and to measurements of inclusively selected jets. In pp collisions, a different jet fragmentation function in photon-tagged events from that in inclusive jet events arises from the difference in fragmentation between light quarks and gluons. The ratios of the fragmentation functions in Pb+Pb events to that in pp events are used to explore the parton color-charge dependence of jet quenching in the hot medium. In relatively peripheral collisions, fragmentation functions exhibit a similar modification pattern for photon-tagged and inclusive jets. However, photon-tagged jets are observed to have larger modifications than inclusive jets in central Pb+Pb events. © 2019 CERN.
Citation - WoS: 63
Citation - Scopus: 80
Constraints on Off-Shell Higgs Boson Production and the Higgs Boson Total Width in Zz › 4l and Zz › 2l2? Final States With the Atlas Detector
(Elsevier B.V., 2018-11) The ATLAS Collaboration; Sultansoy, Saleh
A measurement of off-shell Higgs boson production in the ZZ→4ℓ and ZZ→2ℓ2ν decay channels, where ℓ stands for either an electron or a muon, is performed using data from proton–proton collisions at a centre-of-mass energy of s=13 TeV. The data were collected by the ATLAS experiment in 2015 and 2016 at the Large Hadron Collider, and they correspond to an integrated luminosity of 36.1fb−1. An observed (expected) upper limit on the off-shell Higgs signal strength, defined as the event yield normalised to the Standard Model prediction, of 3.8 (3.4) is obtained at 95% confidence level (CL). Assuming the ratio of the Higgs boson couplings to the Standard Model predictions is independent of the momentum transfer of the Higgs production mechanism considered in the analysis, a combination with the on-shell signal-strength measurements yields an observed (expected) 95% CL upper limit on the Higgs boson total width of 14.4 (15.2) MeV. © 2018 The Author
Citation - WoS: 25
Citation - Scopus: 24
Conventional and Rapid Thermal Annealing of Spray Pyrolyzed Copper Indium Gallium Sulfide Thin Films
(Elsevier Science Sa, 2014) Aydın, Erkan; Sankır, Mehmet; Demirci Sankır, Nurdan
With this study for the first time effects of post annealing on morphological, structural, optical and electrical properties of spray pyrolyzed copper-indium-gallium-sulfide (CuInGaS2) thin films have been investigated. Pros-and-cons of conventional (CA) and rapid thermal annealing (RTA) have been discussed to obtain the high quality thin film absorbers for solar cell applications. X-ray diffraction analysis revealed that all of the spray pyrolyzed CuInGaS2 thin films have chalcopyrite structures with a highly (112) preferential orientation. Raman spectra also confirmed this structure. However, metal oxide secondary phases such as copper oxide and gallium oxide were detected when the temperature ramp rate was increased during RTA process. Energy dispersive X-ray measurements revealed that both copper and gallium diffused through the surface after annealing processes. Moreover, copper diffusion became pronounced especially at high annealing temperatures. Optical transmission measurements in the wavelength range between 600 and 1100 nm showed that band gap energy of CuInGaS2 thin films was ranging between 1.36 and 1.51 eV depending on the annealing conditions. Very high mobility values have been observed for both processes. The maximum electrical mobility, 30.9 cm(2)/V s, was observed for the films annealed at 600 degrees C via CA. This is the highest reported value among the CuInGaS2 thin film absorbers deposited by both solution and vacuum based techniques. As a result, post-annealing of spray pyrolyzed CuInGaS2 thin films without usage of highly toxic gases, reported in this study, is very promising and environmentally friendly method to produce solar cell quality absorber layers. (C) 2014 Elsevier B.V. All rights reserved.
Citation - WoS: 57
Citation - Scopus: 59
Cvd Synthesis and Characterization of Thin Mo2c Crystals
(WILEY, 2020-06) Türker, Furkan; Caylan, Ömer R.; Mehmood, Naveed; Kasırga, Talip S.; Sevik, Cem; Büke, Zarife Göknur
In this study, we present an investigation on the growth of thin Mo2C crystals via chemical vapor deposition using CH4. Optical microscopy (OM), scanning electron microscopy (SEM), atomic force microscopy(AFM), and Raman spectroscopy studies show that the morphology and the thickness of Mo2C crystals are strongly affected by the impurities in the system, the thickness of the copper substrate, and the graphene presence on Cu surface prior to Mo2C formation. Our studies show that during the CVD process, orthorhombic Mo2C crystals grow along the [100] direction on two different regions: directly on Cu surface or on graphene covered regions. Mo2C crystals that form on graphene are found to be thinner and less defective compared to the ones formed on the Cu surface. This is attributed to graphene acting as an additional diffusion barrier for Mo atoms diffusing through the copper. In addition to the graphene beneath the Mo2C crystal, Raman studies indicate that graphene may grow also on top of the Mo2C crystal, forming a graphene/Mo2C/graphene sandwich structure which may offer interesting properties for electronic applications.
Citation - WoS: 15
Citation - Scopus: 18
A Data-Driven Optimization Framework for Routing Mobile Medical Facilities
(Springer, 2020) Yücel, Eda; Salman, F. Sibel; Bozkaya, Burcin; Gökalp, Cemre
We study the delivery of mobile medical services and in particular, the optimization of the joint stop location selection and routing of the mobile vehicles over a repetitive schedule consisting of multiple days. Considering the problem from the perspective of a mobile service provider company, we aim to provide the most revenue to the company by bringing the services closer to potential customers. Each customer location is associated with a score, which can be fully or partially covered based on the proximity of the mobile facility during the planning horizon. The problem is a variant of the team orienteering problem with prizes coming from covered scores. In addition to maximizing total covered score, a secondary criterion involves minimizing total travel distance/cost. We propose a data-driven optimization approach for this problem in which data analyses feed a mathematical programming model. We utilize a year-long transaction data originating from the customer banking activities of a major bank in Turkey. We analyze this dataset to first determine the potential service and customer locations in Istanbul by an unsupervised learning approach. We assign a score to each representative potential customer location based on the distances that the residents have taken for their past medical expenses. We set the coverage parameters by a spatial analysis. We formulate a mixed integer linear programming model and solve it to near-optimality using Cplex. We quantify the trade-off between capacity and service level. We also compare the results of several models differing in their coverage parameters to demonstrate the flexibility of our model and show the impact of accounting for full and partial coverage.
Citation - WoS: 118
Citation - Scopus: 124
Design and Fabrication of Branched Polyamine Functionalized Mesoporous Silica: an Efficient Absorbent for Water Remediation
(Amer Chemical Soc, 2014) Nayab, Sana; Farrukh, Aleeza; Oluz, Zehra; Tuncel, Eylül; Tariq, Saadia Rashid; Rahman, Habib ur; Yameen, Basit
A novel branched polyamine (polyethyleneimine, PEI) functionalized mesoporous silica (MS) adsorbent is developed via a facile "grafting-to" approach. X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared (FT-IR) spectroscopy verified the effective surface functionalization of MS with monolayer and polymer. The transmission electron microscopy (TEM) was employed to reveal the morphology of the fabricated materials. The adsorption behavior of the polyamine functionalized mesoporous silica (MS-PEI) is assessed against anionic dyes. The adsorbent characteristics of MS-PEI are compared with a monolayer platform comprising of 3-aminopropyltriethoxy silane (APTES) functionalized mesoporous silica (MS-APTES). The adsorption behavior of the MS-PEI and MS-APTES toward anionic dyes is further evaluated by studying the effect of adsorbent dosage, pH, contact time, and temperature. Langmuir and Freundlich isotherm models are employed to understand the adsorption mechanism. The obtained kinetic data support a pseudo-second-order adsorption behavior for both monolayer and polymer functionalized MS. The associated thermodynamic parameters (Delta G degrees, Delta H degrees, and Delta S degrees) reveal that the process of adsorption with MS-PEI is more spontaneous and energetically favored as compared to the adsorption with MS-APTES. Taken together, the novel adsorbent system derived from a combination of MS and branched polymer (MS-PEI) shows the higher absorption efficiency and capacity toward the anionic dyes than the monolayer based adsorbent (MS-APTES).
Citation - WoS: 116
Citation - Scopus: 140
Design of Polymer-Brush Magnetic Nanoparticles for Highly Efficient Water Remediation
(Amer Chemical Soc, 2013) Farrukh, Aleeza; Akram, Attia; Ghaffar, Abdul; Hanif, Sara; Hamid, Almas; Duran, Hatice; Yameen, Basit
Highly efficient removal of mercury(II) ions (Hg-II) from water has been reported by employing polymer-brush-functionalized magnetic nanoparticles (MNPs). Surface-initiated conventional radical polymerization (SI-cRP) was used to grow poly(2-aminoethyl methacrylate hydrochloride) (poly-AEMA center dot HCl) polymer chains on magnetite nanoparticles (Fe3O4), followed by the transformation of pendant amino groups into dithiocarbamate (DTC) groups, which showed high chelating affinity toward Hg-II ions. This polymer-brush-based DTC-functionalized MNP (MNPs-polyAEMA center dot DTC) platform showed the complete removal of Hg-II from aqueous solutions. The Hg-II ion removal capacity and efficiency of MNPs-polyAEMA center dot DTC were compared with its monolayer analogue, which was derived from the direct transformation of amino groups of (3-aminopropyl) triethoxysilane (APTES)-functionalized MNPs (MNPs-APTES) to DTC functional groups (MNPs-DTC). The surface chemical modifications and higher chelating functional group density, in the case of MNPs-polyAEMA center dot DTC, were ascertained by transmission electron microscopy (TEM), thermogravimetric analysis (TGA), physical property measurement system (PPMS), attenuated total reflectance infrared (ATR-IR) spectroscopy, and X-ray photoelectron spectroscopy (XPS). The Hg-II ion removal capacity and efficiency of monolayer and polymer-brush-based DTC-functionalized MNPs (MNPs-DTC and MNPs-polyAEMA center dot DTC, respectively) were evaluated and compared by studying the effect of various factors on the percentage removal of Hg-II such as adsorbent amount, temperature, and contact time. Furthermore, the adsorption behavior of MNPs-DTC and MNPs-polyAEMA center dot DTC was analyzed by applying Langmuir and Freundlich adsorption isotherm models. In addition, the adsorption thermodynamics, as well as the adsorption kinetics, were also evaluated in detail. The higher surface functional group density of MNPs-polyAEMA center dot DTC led to superior remediation characteristics toward Hg-II ions than its monolayer analogue.
Citation - WoS: 2
Citation - Scopus: 1
Dynamics of Ultra-Thin Polystyrene With and Without a (artificial) Dead Layer Studied by Resonance Enhanced Dynamic Light Scattering
(Amer Inst Physics, 2017) Vianna, S. D. B.; Lin, F. Y.; Plum, M. A.; Duran, H.; Steffen, W.
Using non-invasive, marker-free resonance enhanced dynamic light scattering, the dynamics of capillary waves on ultrathin polystyrene films' coupling to the viscoelastic and mechanical properties have been studied. The dynamics of ultrathin polymer films is still debated. In particular the question of what influence either the solid substrate and/or the fluid-gas interface has on the dynamics and the mechanical properties of films of glass forming liquids as polymers is in the focus of the present research. As a consequence, e.g., viscosity close to interfaces and thus the average viscosity of very thin films are prone to change. This study is focused on atactic, non-entangled polystyrene thin films on the gold surface. A slow dynamic mode was observed with Vogel-Fulcher-Tammann temperature dependence, slowing down with decreasing film thickness. We tentatively attribute this relaxation mode to overdamped capillary waves because of its temperature dependence and the dispersion with a wave vector which was found. No signs of a more mobile layer at the air/polymer interface or of a "dead layer" at the solid/polymer interface were found. Therefore we investigated the influence of an artificially created dead layer on the capillary wave dynamics by introducing covalently bound polystyrene polymer brushes as anchors. The dynamics was slowed down to a degree more than expected from theoretical work on the increase of density close to the solid liquid interface-instead of a "dead layer" of 2 nm, the interaction seems to extend more than 10 nm into the polymer. Published by AIP Publishing.
Citation - WoS: 11
Citation - Scopus: 12
The E-6 Inspired Isosinglet Quark and the Higgs Boson
(Elsevier, 2008) Sultansoy, Saleh; Ünel, Gökhan
We consider the experimental implications of the down type isosinglet quark, D, predicted by the E-6, group to Higgs boson searches at the LHC. The pair production of D quarks at the LHC and their subsequent decays D -> hd and D -> Wu has been analyzed. For a light Higgs boson of mass O(120 GeV), an analysis based on fast simulation of the ATLAS detector response shows that the b (b) over bar channel becomes as efficient as the gamma gamma channel for discovering the Higgs particle if m(D) < 630 GeV. Published by Elsevier B.V.
Citation - WoS: 7
Citation - Scopus: 8
The Effects of Acid Pretreatment and Surface Stresses on the Evolution of Impurity Clusters and Graphene Formation on Cu Foil
(ELSEVIER SCIENCE BV, 2017-12) Senyıldız, Doğukan; Oğurtani, Ömer Tarık; Büke, Zarife Göknur
In this study, the effects of acid pretreatment together with the surface stresses are studied systematically to control the densities of Si and Ca based impurities on the surface and to understand their effects on the final graphene morphology formed on Cu foil via CVD. In order to investigate the surface coverage and morphology of graphene, in addition to scanning electron microscope (SEM) studies, graphene grown on Cu foils are oxidized in air to reveal the graphene domains under the optical microscope (OM). Graphene formation is also confirmed using Raman spectroscopy directly on the Cu foil. Our studies show that the coverage and the morphology of the final graphene are strongly affected by the acid pretreatment because it removes the surface oxide layer and surface Ca impurities inherently present on the copper foil. Furthermore, it is found that the surface elastic stresses have also direct influence on the sizes and distribution of the surface impurities which affect the final morphology of graphene. (C) 2017 Elsevier B.V. All rights reserved.
Citation - WoS: 4
Citation - Scopus: 4
Enhanced Interfacial Rigidity of 1d Thermoset Nanostructures by Interface-Induced Liquid Crystallinity
(Royal Soc Chemistry, 2013) Duran, Hatice; Yameen, Basit; Geuss, Markus; Kappl, Micheal; Steinhart, Martin; Knoll, Wolfgang
Polycyanurate networks (PCNs), which form random networks in the bulk, are representative of an important class of thermosetting materials. We show that free surfaces of PCNs exhibit rigidity enhanced by one order of magnitude (quantified by Young's modulus) if they are initially synthesized in the presence of hard confining interfaces, such as the pore walls of nanoporous anodic aluminum oxide (AAO). Using self-ordered AAO, which contains arrays of aligned cylindrical nanopores uniform in length and diameter as an inorganic model matrix, we could evidence interface-induced liquid-crystalline ordering of the liquid cyanate ester monomers (CEMs) at the pore walls. The interfacial ordering of the CEMs, which is conserved upon curing, is most likely the origin of enhanced rigidity of the free PCN surfaces after release of the one-dimensional PCN nanostructures from AAO. The results presented here should be of considerable relevance for the processing of industrially relevant thermosets, for the understanding of polymer/solid interfaces, for the design of advanced nanocomposites for applications in aviation and high-speed electronics, and for the design of mechanical hybrid nanostructures for advanced biomimetic adhesive systems.

Browse

Browsing Malzeme Bilimi ve Nanoteknoloji Mühendisliği Bölümü / Department of Material Science & Nanotechnology Engineering by WoS Q "Q1"