Fiber optic sensors based on hybrid phenyl-silica xerogel films to detect n-hexane: determination of the isosteric enthalpy of adsorption

• Jesús C. Echeverría,
• Ignacio Calleja,
• Paula Moriones and
• Julián J. Garrido

Beilstein J. Nanotechnol. 2017, 8, 475–484, doi:10.3762/bjnano.8.51

• the siloxane bonds. In particular, the decrease in the maximum of the angle 2θ is related to the elongation of the silanol bond due to the inductive and steric effects of phenyl groups. The N2 adsorption–desorption isotherms at 77 K are shown in Figure 3. The three isotherms belong to type IV with

• hysteresis loops of type H-2, according to the International Union of Pure and Applied Chemistry classification [17]. The Type IV isotherms are characteristic of mesoporous materials common in many inorganic oxide gels having interconnected pore networks. The amount of adsorbed N2 decreased with an increase

• common in most N2 isotherms. This phenomenon is related to the irreversible adsorption in pores with opening diameters close to the kinetic diameter of the adsorbate [25]. For the PhTEOS hybrid xerogels, the non-closure of the hysteresis loop could be associated with the presence of cage-like domains in

Tailoring bifunctional hybrid organic–inorganic nanoadsorbents by the choice of functional layer composition probed by adsorption of Cu²⁺ ions

• Veronika V. Tomina,
• Inna V. Melnyk,
• Yuriy L. Zub,
• Aivaras Kareiva,
• Miroslava Vaclavikova,
• Gulaim A. Seisenbaeva and
• Vadim G. Kessler

Beilstein J. Nanotechnol. 2017, 8, 334–347, doi:10.3762/bjnano.8.36

• adsorption isotherms are presented in Figure 5. To determine the formal coordination surrounding of Cu(II) ions in the adsorption layer, the isotherms were plotted in the form of CsCu:CsR as a function of C0Cu:C0R (Figure 6, Figure S8, Supporting Information File 1). These data were complemented by EPR and

• , the maximum of this band is at about 13000–14000 cm−1. We measured adsorption isotherms of n-hexane, acetonitrile and water (Figure S10, Supporting Information File 1) to compare the properties of silica nanoparticles with fluorine (see Supporting Information File 1) and amino/perfluoroalkyl

• -containing bifunctional surface layers. In the case of bifunctional sample NF2, at low fillings, the three vapor adsorption isotherms of n-hexane, acetonitrile, and water coincide. However, with increasing P/Ps values, motre acetonitrile is adsorbed compared to water and n-hexane. During the synthesis, the

Nanoscale isoindigo-carriers: self-assembly and tunable properties

• Tatiana N. Pashirova,
• Andrei V. Bogdanov,
• Lenar I. Musin,
• Julia K. Voronina,
• Irek R. Nizameev,
• Marsil K. Kadirov,
• Vladimir F. Mironov,
• Lucia Ya. Zakharova,
• Shamil K. Latypov and
• Oleg G. Sinyashin

Beilstein J. Nanotechnol. 2017, 8, 313–324, doi:10.3762/bjnano.8.34

• tension isotherms of SDS with 2a additives (Figure 6a) and the decrease of the slope, indicating a lower surface activity. This is presumably related to the formation of structures with various aggregation numbers. Measurement of the size of 2а particles in SDS solution showed the presence of particles of

• −6 M, 25 °C. Absorbance of 2a, 2b, 2d–g at λmax ≈ 395 nm and 1g, 3 at λmax = 300 nm in aqueous micellar SDS solution; 25 °C, optical path 1 cm and solubility profile solution of SDS in the presence of 2a on concentration of SDS, cSDS= 2–80 mM, 25 °C. (a) Surface tension isotherms of SDS in the

Functionalized TiO₂ nanoparticles by single-step hydrothermal synthesis: the role of the silane coupling agents

• Antoine R. M. Dalod,
• Lars Henriksen,
• Tor Grande and
• Mari-Ann Einarsrud

Beilstein J. Nanotechnol. 2017, 8, 304–312, doi:10.3762/bjnano.8.33

• the crystallite sizes determined by XRD, which suggest only weakly agglomeration in the powders after drying. The nitrogen adsorption and desorption isotherms of TiO2 and in situ surface-functionalized TiO2 nanoparticles demonstrate the hysteresis profile similar to mesoporous materials (Figure 4a

• ). Since particle sizes from SEM and surface area are similar, porosity is associated with inter-particle volume of the agglomerates and can be directly correlated with the particle sizes [34]. Figure 4b displays the pore size distribution from desorption isotherms of TiO2 and in situ surface

• , and (d) Ti-AEAPS. (a) Adsorption (solid symbols) and desorption (open symbols) isotherms and (b) BJH desorption dV/dlog(D) pore volume, from nitrogen adsorption measurements, of TiO2 and in situ surface-functionalized TiO2 nanoparticles. (a) TGA curves and (b) FTIR spectra of TiO2 and in situ surface

Nanocrystalline TiO₂/SnO₂ heterostructures for gas sensing

• Barbara Lyson-Sypien,
• Anna Kusior,
• Mieczylaw Rekas,
• Jan Zukrowski,
• Marta Gajewska,
• Katarzyna Michalow-Mauke,
• Thomas Graule,
• Marta Radecka and
• Katarzyna Zakrzewska

Beilstein J. Nanotechnol. 2017, 8, 108–122, doi:10.3762/bjnano.8.12

• area (SSA) was determined using Brunauer–Emmett–Teller (BET) nitrogen-adsorption isotherms obtained with a Beckman–Coulter SA3100 apparatus. The crystallographic structure was analyzed on the basis of XRD patterns recorded in Bragg–Brentano configuration with the help of a Philips X’Pert Pro

Organoclay hybrid materials as precursors of porous ZnO/silica-clay heterostructures for photocatalytic applications

• Marwa Akkari,
• Pilar Aranda,
• Abdessalem Ben Haj Amara and
• Eduardo Ruiz-Hitzky

Beilstein J. Nanotechnol. 2016, 7, 1971–1982, doi:10.3762/bjnano.7.188

• ZnO/clay/SiO2 ratio because of the difficulty to ascertain how much of the Si contribution is coming from the clay silicate and how much from the generated silica. The porous nature of ZnO/SiO2-montmorillonite materials was characterized by nitrogen adsorption–desorption isotherms at 77 K (Figure 5

• type of isotherm (type I with H4 hysteresis loop) (Figure 5B). The textural parameters calculated from these isotherms are summarized in Table 1, where they are compared to related porous materials including the SiO2-clay hetererostructures without ZnO NP and previously reported ZnO-clay

• 4.5 and 6 µs recycle delay between accumulations and nearly 3000 accumulations. The 29Si chemical shifts were evaluated in relation to tetramethylsilane. Nitrogen adsorption/desorption isotherms at −196 °C were obtained in a Micromeritics ASAP 2010 analyzer. Before measurement, the samples (150–200 mg

In situ formation of reduced graphene oxide structures in ceria by combined sol–gel and solvothermal processing

• Jingxia Yang,
• Johannes Ofner,
• Bernhard Lendl and
• Ulrich Schubert

Beilstein J. Nanotechnol. 2016, 7, 1815–1821, doi:10.3762/bjnano.7.174

• –CeO2 composites with different proportions of added rGO (c–f) after solvothermal treatment in ethanol. Morphologies of rGO(0)–CeO2 (a1: TEM, a2: HRTEM) and rGO(0.05)–CeO2 (b1: TEM, b2: HRTEM). N2 adsorption–desorption isotherms (left) and pore size distributions (right) for CeO2 with rGO-like organic

Nanostructured TiO₂-based gas sensors with enhanced sensitivity to reducing gases

• Wojciech Maziarz,
• Anna Kusior and
• Anita Trenczek-Zajac

Beilstein J. Nanotechnol. 2016, 7, 1718–1726, doi:10.3762/bjnano.7.164

• is very narrow and it is possible that application of much higher values would result in gradual flattening. This behavior is related to adsorption processes that take place on the surface of the sensor and can be described by suitable isotherms, i.e., the empirical Langmuir isotherm [41]. At a fixed

Development of adsorptive membranes by confinement of activated biochar into electrospun nanofibers

• Mehrdad Taheran,
• Mitra Naghdi,
• Satinder K. Brar,
• Emile Knystautas,
• Mausam Verma,
• Rao. Y. Surampalli and
• Jose. R. Valero

Beilstein J. Nanotechnol. 2016, 7, 1556–1563, doi:10.3762/bjnano.7.149

• (BET) specific surface areas were obtained from the N2 adsorption isotherms recorded at 77 K using an Autosorb-1 gas analyzer (Quantachrome Instruments, USA) in the relative pressure range from 0.05 to 1. Thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) were performed using

• addition of activated biochar was a significant contributor (p-value = 0.040, F factor = 11.56) to enhancement of specific surface area. The nitrogen adsorption isotherms at 77 K against relative pressure and differential and cumulative pore surface area against pore width for NFM-0% and NFM-1.5% are

• plotted in Figure 3 and Figure 4. The adsorption isotherms indicated that raw NFM-0% had a significantly lower N2 adsorption capacity than NFM-1.5%; they had a total pore volume of 0.024 and 0.128 mL/g at 0.99 P/P0, respectively. According to the differential surface area curves in Figure 4, NFM-0% had

Three-gradient regular solution model for simple liquids wetting complex surface topologies

• Sabine Akerboom,
• Marleen Kamperman and
• Frans A. M. Leermakers

Beilstein J. Nanotechnol. 2016, 7, 1377–1396, doi:10.3762/bjnano.7.129

• -called adsorption isotherms. Of course we need a solubility gap and thus χ > 2 (we use a value of 2.2 throughout). Next, we consider a specific value of χS < 0 and specify a given amount of solvent in the system. We solve the self-consistent field equations and obtain the optimised density profile φ(z

• ). Far from the surface, the density profile converges to the bulk value φb. The adsorbed amount (surface excess) of liquid is found by: We focus on how the adsorption isotherms, Γσ(φb), behave near the bulk binodal φ#. When upon the approach of the bulk binodal the adsorbed amount simply increases and

• molecules in the slit. This reference value is used to compute the isotherms. In Figure 5A we present an example for a slit distance D = 10 (in lattice units) and our default interaction parameters χ = 2.2 and χS = −0.3. Recall that under these conditions the surfaces are preferentially solvated by the

High performance Ce-doped ZnO nanorods for sunlight-driven photocatalysis

• Bilel Chouchene,
• Tahar Ben Chaabane,
• Lavinia Balan,
• Emilien Girot,
• Kevin Mozet,
• Ghouti Medjahdi and
• Raphaël Schneider

Beilstein J. Nanotechnol. 2016, 7, 1338–1349, doi:10.3762/bjnano.7.125

• ZnO and 5% doped ZnO:Ce rods were also investigated using nitrogen adsorption–desorption experiments (Figure 7). The N2 adsorption–desorption isotherms are of type II for both materials, according to the Brunauer–Dening–Dening–Teller (BDDT) classification [55]. Both materials exhibit high adsorption

• Characterization Analyzer instrument using liquid nitrogen (−196 °C). Prior to the analyses, the samples were out-gassed overnight under primary vacuum at 40 °C on the ports of the Micromeritics VacPrep 061 degasser followed by 4 h out-gassing under high vacuum on the analyse ports. The resulting isotherms were

Mesoporous hollow carbon spheres for lithium–sulfur batteries: distribution of sulfur and electrochemical performance

• Anika C. Juhl,
• Artur Schneider,
• Boris Ufer,
• Torsten Brezesinski,
• Jürgen Janek and
• Michael Fröba

Beilstein J. Nanotechnol. 2016, 7, 1229–1240, doi:10.3762/bjnano.7.114

• sulfur. Nevertheless, the results have to be handled with care because of the vacuum applied while degassing and measuring the samples. From the physisorption isotherms the pore volume of the shell of the HCS/sulfur composites can be determined in the same way as that of the pure hollow spheres (see

• Figure S8 in Supporting Information File 1 for the physisorption isotherms and plots of cumulative pore volumes). For comparison, a theoretical pore volume can be calculated from the pore volume of HCS and the volume of the impregnated sulfur according to Equation 5 (for the derivation see Supporting

An ellipsometric approach towards the description of inhomogeneous polymer-based Langmuir layers

• Falko O. Rottke,
• Burkhard Schulz,
• Klaus Richau,
• Karl Kratz and
• Andreas Lendlein

Beilstein J. Nanotechnol. 2016, 7, 1156–1165, doi:10.3762/bjnano.7.107

• –expansion isotherms are shown in Figure 1. The π–A isotherm is identical to that of an already investigated PPDL-based Langmuir layer, namely OPDL–TMDI [17], which consists of oligo(ω-pentadecalactone) segments linked by the urethane linker TMDI (2,2,4-trimethyl-hexamethylene diisocyanate). The mean

Assembling semiconducting molecules by covalent attachment to a lamellar crystalline polymer substrate

• Rainhard Machatschek,
• Patrick Ortmann,
• Renate Reiter,
• Stefan Mecking and
• Günter Reiter

Beilstein J. Nanotechnol. 2016, 7, 784–798, doi:10.3762/bjnano.7.70

Cantilever bending based on humidity-actuated mesoporous silica/silicon bilayers

• Christian Ganser,
• Gerhard Fritz-Popovski,
• Roland Morak,
• Parvin Sharifi,
• Benedetta Marmiroli,
• Barbara Sartori,
• Heinz Amenitsch,
• Thomas Griesser,
• Christian Teichert and
• Oskar Paris

Beilstein J. Nanotechnol. 2016, 7, 637–644, doi:10.3762/bjnano.7.56

• water sorption isotherms measured for similar materials, indicating the different pressures for capillary condensation during adsorption and capillary evaporation during desorption, respectively, in pores with quite monodisperse size distributions [22]. It is well known that adsorption and desorption of

• strain isotherms [13][27][37], with a sudden drop of the strain at capillary condensation. The reason, why there is no such strain drop seen in Figure 4 (and Figure 2) at the pressure of capillary condensation (RH ≈ 70%) is not fully clear. Theoretical calculations [13][39] and experiments with water in

Comparison of the interactions of daunorubicin in a free form and attached to single-walled carbon nanotubes with model lipid membranes

• Dorota Matyszewska

Beilstein J. Nanotechnol. 2016, 7, 524–532, doi:10.3762/bjnano.7.46

• prepared with either prevailing weight ratio of nanotubes or prevailing weight ratio of thiolipid. The isotherms are shown in Figure 2. Despite the fact that the experimental procedure differed in case of the two investigated forms of the drug (free drug was dissolved in the subphase, while drug-carbon

• caused by the incorporation of DNR molecules into the thiolipid layer. Additionally, the shape of the isotherms is altered and the broad plateau region corresponding to the phase transition is clearly visible at relatively high surface pressure of 38 mN/m (Figure 2). Significant changes concern the

• when daunorubicin attached to carbon nanotubes is introduced into DPPTE monolayers. In case of mixed DPPTE–SWCNTs-DNR layer the isotherms are only slightly altered. When the amount of drug carrier is relatively small compared to the prevailing amount of the lipid (DPPTE/SWCNTs-DNR weight ratio of 10:1

Influence of calcium on ceramide-1-phosphate monolayers

• Joana S. L. Oliveira,
• Gerald Brezesinski,
• Alexandra Hill and
• Arne Gericke

Beilstein J. Nanotechnol. 2016, 7, 236–245, doi:10.3762/bjnano.7.22

• -defined pH environment. For that purpose, we used monomolecular films of C1P at the soft air/liquid interface with calcium ions in the subphase. The pH was varied to change the protonation degree of the C1P head group. We used surface pressure versus molecular area isotherms coupled with other monolayer

• techniques as Brewster angle microscopy (BAM), infrared reflection–absorption spectroscopy (IRRAS) and grazing incidence X-ray diffraction (GIXD). The isotherms indicate that C1P monolayers are in a condensed state in the presence of calcium ions, regardless of the pH. At higher pH without calcium ions, the

• environment. Results and Discussion The C1P monolayer was studied at pH 4 and pH 9. While at pH 9 the head groups of C1P should be mostly deprotonated and therefore twofold negatively charged, these groups are highly protonated at pH 4. Figure 2 displays the surface pressure–area isotherms at pH 4 and pH 9

Characterisation of thin films of graphene–surfactant composites produced through a novel semi-automated method

• Nik J. Walch,
• Alexei Nabok,
• Frank Davis and
• Séamus P. J. Higson

Beilstein J. Nanotechnol. 2016, 7, 209–219, doi:10.3762/bjnano.7.19

• spectrum of graphite (blue). Surface pressure/area isotherms of graphene(+)CTAB monolayers on the water surface. Numbers 1, 2, and 3 indicate consecutive compressions of the monolayer. AFM images of the same sample of a graphene(+)CTAB layer deposited onto a silicon substrate using the LS method: (a) 2D

Controlled graphene oxide assembly on silver nanocube monolayers for SERS detection: dependence on nanocube packing procedure

• Martina Banchelli,
• Bruno Tiribilli,
• Roberto Pini,
• Luigi Dei,
• Paolo Matteini and
• Gabriella Caminati

Beilstein J. Nanotechnol. 2016, 7, 9–21, doi:10.3762/bjnano.7.2

• interface to obtain ordered floating monolayers, in addition we observed that the shape and position of π–A isotherms strongly depend on factors such as the time allowed for solvent evaporation before starting compression, the amount of substance spread at the interface and the compression speed. Careful

• optimization of these parameters generated reproducible isotherms up to π = 20 mN/m, compression beyond this value leads to unstable monolayers due to incipient collapse of the film and formation of 3D structure. A typical π–A isotherm for AgNCs is reported in Figure 1a together with the behaviour of the

• ± 0.5 °C (Haake thermostatic bath, Germany). Continuous spreading isotherms and hysteresis cycles were obtained using the same barrier speed of 20 mm min−1 in both directions. The reported results are the average of at least three independent measurements. Langmuir–Blodgett films were transferred, after

pH-Triggered release from surface-modified poly(lactic-co-glycolic acid) nanoparticles

• Manuel Häuser,
• Klaus Langer and
• Monika Schönhoff

Beilstein J. Nanotechnol. 2015, 6, 2504–2512, doi:10.3762/bjnano.6.260

• , leading to well fitted desorption isotherms. Furthermore, desorption data obtained after omitting the previous adsorption of a terminating PAA layer clearly show a partial desorption of PDADMAC during assembly of the terminating PAA layer, emphasising the pH-sensitivity of PEM consisting of weak

Green synthesis, characterization and catalytic activity of natural bentonite-supported copper nanoparticles for the solvent-free synthesis of 1-substituted 1H-1,2,3,4-tetrazoles and reduction of 4-nitrophenol

• Akbar Rostami-Vartooni,
• Mohammad Alizadeh and
• Mojtaba Bagherzadeh

Beilstein J. Nanotechnol. 2015, 6, 2300–2309, doi:10.3762/bjnano.6.236

• by FE-SEM (Cam scan MV2300). The chemical composition of the modified bentonite was measured by EDX performed in a SEM. TEM images were obtained using a Philips-EM-2085 transmission electron microscope with an accelerating voltage of 100 kV. Nitrogen adsorption isotherms were performed on a

• volumetric gas adsorption apparatus (BEL Japan, Belsorp-max). The pore distributions and pore volumes were calculated using the adsorption branch of the N2 isotherms based on the Barrett–Joyner–Halenda (BJH) model. The specific surface area was calculated from the BET equation. Preparation of Thymus vulgaris

Influence of wide band gap oxide substrates on the photoelectrochemical properties and structural disorder of CdS nanoparticles grown by the successive ionic layer adsorption and reaction (SILAR) method

• Mikalai V. Malashchonak,
• Alexander V. Mazanik,
• Olga V. Korolik,
• Еugene А. Streltsov and
• Anatoly I. Kulak

Beilstein J. Nanotechnol. 2015, 6, 2252–2262, doi:10.3762/bjnano.6.231

• using an ASAP2020MP analyzer (Micromeritics, USA). Adsorption isotherms were obtained with N2 at 77 K. The surface area was calculated from the linear part of the BET plot. X-ray diffraction analysis was carried out on a Bruker D8 Advance diffractometer using Cu Kα radiation in the Bragg–Brentano

Nanofibers for drug delivery – incorporation and release of model molecules, influence of molecular weight and polymer structure

• Jakub Hrib,
• Jakub Sirc,
• Radka Hobzova,
• Zuzana Hampejsova,
• Zuzana Bosakova,
• Marcela Munzarova and
• Jiri Michalek

Beilstein J. Nanotechnol. 2015, 6, 1939–1945, doi:10.3762/bjnano.6.198

• calculated based on nitrogen absorption/desorption isotherms recorded on an ASAP 2020 apparatus Micromeritics, USA. In vitro polyethylene glycol release assay Samples of nanofibers (0.3 g) were placed into glass vials filled with 5 mL of distilled water. The samples were continuously shaken at room

Continuum models of focused electron beam induced processing

• Milos Toth,
• Charlene Lobo,
• Vinzenz Friedli,
• Aleksandra Szkudlarek and
• Ivo Utke

Beilstein J. Nanotechnol. 2015, 6, 1518–1540, doi:10.3762/bjnano.6.157

• monolayer limit 1/Ap. At the lower substrate temperatures of 300 and 200 K, kconv, kp and kc are reduced through Equation 41, Equation 42 and Equation 43, yielding the adsorption isotherms shown in Figure 13a. It is important to note that the rate of chemisorption is always limited by the activation barrier

Heterometal nanoparticles from Ru-based molecular clusters covalently anchored onto functionalized carbon nanotubes and nanofibers

• Deborah Vidick,
• Xiaoxing Ke,
• Michel Devillers,
• Claude Poleunis,
• Arnaud Delcorte,
• Pietro Moggi,
• Gustaaf Van Tendeloo and
• Sophie Hermans

Beilstein J. Nanotechnol. 2015, 6, 1287–1297, doi:10.3762/bjnano.6.133

• nitrogen adsorption isotherms. XPS reveals the presence of the expected heteroatoms at each step of the functionalization strategy and indicates (from the ratios of atom % on the surface) that each reaction did not proceed with 100% yield and some unreacted sites remained from the previous step. The