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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 973 records · Page 54
All sourcesNASA NTRSDOE OSTI
DOE OSTI2014

Imaging local electric fields produced upon synchrotron X-ray exposure

Electron-hole separation following hard X-ray absorption during diffraction analysis of soft materials under cryogenic conditions produces substantial local electric fields visualizable by second harmonic generation (SHG) microscopy. Monte Carlo simulations of X-ray photoelectron trajectories suggest the formation of substantial local electric fields in the regions adjacent to those exposed to X-rays, indicating a possible electric-field-induced SHG (EFISH) mechanism for generating the observed signal. In studies of amorphous vitreous solvents, analysis of the SHG spatial profiles following X-ray microbeam exposure was consistent with an EFISH mechanism. Within protein crystals, exposure to 12-keV (1.033-angstrom) X-rays resulted in increased SHG in the region extending similar to 3 mu m beyond the borders of the X-ray beam. Moderate X-ray exposures typical of those used for crystal centering by raster scanning through an X-ray beam were sufficient to produce static electric fields easily detectable by SHG. The X-ray-induced SHG activity was observed with no measurable loss for longer than 2 wk while maintained under cryogenic conditions, but disappeared if annealed to room temperature for a few seconds. These results provide direct experimental observables capable of validating simulations of X-ray-induced damage within soft materials. In addition, X-ray-induced local fields may potentially impact diffraction resolution through localized piezoelectric distortions of the lattice.

Dettmar, Christopher M.↗
DOE OSTI2013

Syntheses, structures and photoluminescent properties of three d{sup 10} coordination architectures based on in-situ 1,3,5-triazine derivatives

In the presence of aromatic carboxylic acids, three new d{sup 10} transition metal coordination polymers, [Ag(PAHT)]{sub n}(1), [Ag{sub 2}(HCA)]{sub n}(2) and [Cu{sub 6}(CA){sub 2}(H{sub 2}O)]{sub n}(3) (HPAHT=2-phenyl-4-amino-6-hydroxy-1,3,5-triazine, H{sub 3}CA=cyanuric acid) have been synthesized based on in-situ 1,3,5-triazine derivatives resulting from 2,4-diamino-6-phenyl-1,3,5-triazine, 2-chloro-4,6-diamino-1,3,5-triazine and melamine under hydrothermal conditions. Complexes 1–3 have been characterized by single-crystal X-ray diffraction, IR spectra, elemental analysis and thermogravimetric analysis (TGA). The compound 1 exhibits a uninodal three-connected 3D network with a rare lig LiGe type topology, which contains right-handed and left-handed [Ag(PAHT)]{sub n} helical chains. For compound 2, the 3D network is comprised of 2D sheet by strongly Ag–O and weakly Ag(I)…Ag(I) interactions. In compound 3, it is infrequently observed that dodecanuclear copper(I) units as secondary building units (SBUs) construct 3D network by the ligands CA{sup 3−} with a rare uninodal 10-connected bct topology (3{sup 12}.4{sup 28}.5{sup 5}). The photoluminescent properties of three compounds have also been measured. - Graphical abstract: Three d{sup 10} transition metal coordination polymers 1–3 have been hydrothermally synthesized and characterized by single-crystal X-ray diffraction, IR spectra, elemental analysis, photoluminescent spectra and thermogravimetric analysis (TGA). - Highlights: • The compound 1 exhibits a new 3D network with two kinds of single helical chains. • New 3D d{sup 10} transition metal coordination polymers. • The photoluminescent properties have been measured.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2017

Single-shot structural analysis by high-energy X-ray diffraction using an ultrashort all-optical source

High-energy X-rays (HEX-rays) with photon energies on order of 100 keV have attractive characteristics, such as comparably low absorption, high spatial resolution and the ability to access inner-shell states of heavy atoms. These properties are advantageous for many applications ranging from studies of bulk materials to the investigation of materials in extreme conditions. Ultrafast X-ray diffraction allows the direct imaging of atomic dynamics simultaneously on its natural time and length scale. However, using HEX-rays for ultrafast studies has been limited due to the lack of sources that can generate pulses of sufficiently short (femtosecond) duration in this wavelength range. Here we show single-crystal diffraction using ultrashort ~90 keV HEX-ray pulses generated by an all-optical source based on inverse Compton scattering. We also demonstrate a method for measuring the crystal lattice spacing in a single shot that contains only ~10 5 photons in a spectral bandwidth of ~50% full width at half maximum (FWHM). Our approach allows us to obtain structural information from the full X-ray spectrum. As target we use a cylindrically bent Ge crystal in Laue transmission geometry. As a result, this experiment constitutes a first step towards measurements of ultrafast atomic dynamics using femtosecond HEX-ray pulses.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2024

Embedded High-Temperature Sensors: Enhancing Thermoelectrical Performance with Refractory Composites Gradient Layers

To monitor the stability of various energy and manufacturing systems, sensors capable of operating at temperatures exceeding 1000 °C in diverse environments for extended durations are essential. However, under harsh conditions, degradation of sensing materials is a concern that can be controlled by embedding the sensors into refractory oxides. Doped-LaCrO3 based composites are excellent candidates for high-temperature sensing applications due to their good thermoelectrical properties. However, chemical reactivity between the conductive phase and the refractory oxides can decrease the performance of the sensors. In this work, it was devised gradient-type protective layers safeguarding conductive phases within embedded thermocouples, which were fabricated and characterized by X-Ray Diffraction for phase development analysis, Scanning Electron Microscopy and Energy-dispersive X-ray spectroscopy for microstructure and cationic interdiffusion kinetics, long-term thermoelectric testing was completed up to 1400 °C. The enhanced performance of these novel sensors addresses a critical limitation, rendering them viable for long-term high-temperature applications.

20 FOSSIL-FUELED POWER PLANTS↗
DOE OSTI2015

SnCo–CMK nanocomposite with improved electrochemical performance for lithium-ion batteries

Highlights: • The SnCo–CMK nanocomposite was synthesized using mesoporous carbon as nano-reactor. • Ultrafine SnCo nanoparticles distribute both inside and outside of mesopore channels. • The SnCo–CMK nanocomposite is an alternative anode material for Li-ion intercalation. • A high reversible capacity of 562 mAh g{sup −1} is maintained after 60 cycles at 100 mA g{sup −1}. - Abstract: In the present work, SnCo–CMK nanocomposite was successfully synthesized for the first time via a simple nanocasting route by using mesoporous carbon as nano-reactor. The nanocomposite was then characterized by means of X-ray diffraction (XRD), thermogravimetric analysis (TG), N{sub 2} adsorption–desorption, scanning and transmission electron microscopy (SEM/TEM) respectively. Furthermore, the SnCo–CMK nanocomposite exhibited large reversible capacities, excellent cycling stability and enhanced rate capability when employed as an anode material for lithium-ion batteries. A large reversible capacity of 562 mA h g{sup −1} was obtained after 60 cycles at a current density of 0.1 A g{sup −1} which is attributed to the structure of ‘meso-nano’ SnCo–CMK composite. This unique structure ensures the intimate contact between CMK and SnCo nanoparticles, buffers the large volume expansion and prevents the aggregation of the SnCo nanoparticles during cycling, leading to the excellent cycling stability and enhanced rate capability.

36 MATERIALS SCIENCE↗
DOE OSTI2018

X-ray Diffraction Investigation of Annealing Behavior of Peened Surface Deformation Layer on Precipitation Hardening Stainless Steel

In order to investigate the recrystallization behavior of peened surface deformation layer of precipitation hardening stainless steel, a classic x-ray diffraction line profile analysis, Voigt method, was carried out on peened 17-4PH with different isothermal annealing temperatures. The activation energy of domain boundary migration (Q{sub a}) and the activation energy of microstrain relaxation (Q{sub b}) were calculated by regression analysis in different annealing temperature conditions. The results show that the value of Q{sub a} decreases with annealing temperature increasing, which is due to the influence of precipitation (ε-Cu) size on the movements of grain and subgrain boundaries. The maximum growth rate of ε-Cu particles occurs during 400 to 500 °C interval. Compared with growth behavior of domain size, microstrain relaxation behavior is less sensitive to precipitation particle size. The effects of annealing temperature and time on dislocation density are both significant when annealing temperature is lower than 500 °C. However, the effect of annealing temperature on dislocation density becomes insignificant when annealing temperature is higher than 500 °C. 300 °C annealing temperature only leads to the microstrain relaxation but nearly cannot lead to the domain size growth even if prolonging annealing time. Microstructure enhancement effect still exists in plastic deformation layer when 300 °C annealing temperature lasts for 60 min but nearly disappears when 600 °C annealing temperature lasts for 20 min.

36 MATERIALS SCIENCE↗
DOE OSTI2018

Effect of Dynamic Strain Aging on Tensile Deformation of 20MnMoNi55 Alloy

Results obtained from the uniaxial tensile tests of 20MnMoNi55 low-alloy RPV steel at different temperatures (varying from 27 to 450 °C) and straining rates (varying from 10{sup −5} to 10{sup −1} s{sup −1}) reveal that the material response is sensitive to both temperature and strain rate. For the range of temperature varying from 200 to 400 °C, in combination with different strain rates, the material shows negative strain rate sensitivity along with different kinds of serrated flow (between 200 and 310 °C), commonly termed as Portevin–Le Chatelier effect (types A, B and C). The material behavior, in that temperature–strain rate window, is described by dynamic strain aging (DSA) effect, and the changes in the mechanical properties of the material are studied. The DSA attribute of 20MnMoNi55 steel is characterized by calculating the activation energy. The x-ray diffraction technique and atomic percentage analysis using energy-dispersive x-ray suggest that the manganese influences the interstitial (carbon and/or nitrogen) diffusion by forming Mn-C and/or Mn-N pair, which can be a plausible cause of DSA in the material.

36 MATERIALS SCIENCE↗
DOE OSTI2025

A green degumming approach for lignocellulosic kenaf bast using ethanolamine deep eutectic solvent

Traditional chemical degumming methods for lignocellulosic bast fibers pose substantial challenges, especially when dealing with kenaf bast, which has a high lignin content. Here, these challenges include severe pollution and low efficiency, etc. Therefore, this study developed a novel, green, and efficient degumming approach for lignocellulosic kenaf bast, leveraging choline chloride-ethanolamine (ChCl-ETA) alkaline deep eutectic solvent (DES). The efficacy of the ChCl-ETA DES based degumming method was validated through comprehensive chemical composition analysis, scanning electron microscopy (SEM), Fourier transform infrared (FT-IR) spectroscopy, X-ray diffraction (XRD), thermogravimetric analysis (TG), and two-dimensional (2D) nuclear magnetic resonance (NMR) spectroscopy. Subsequently, the optimal degumming conditions, with a choline chloride to ethanolamine ratio of 1:6 and a degumming temperature of 120 °C, were determined based on the results of the residual gum content. Significantly, the recycled ChCl-ETA DES mixtures could maintain a degumming capacity (revealed by the residual gum content of degummed fibers) comparable to that of the conventional double-boiling method for at least five degumming cycles without purification. Given its low-pollution process and high efficiency, this developed method holds great potential for industrial-scale applications of lignocellulosic bast fibers.

Choline chloride↗
DOE OSTI2013

Two new coordination polymers constructed by naphthalene-1,4-dicarboxylic acid and 2,4-diamino-6-methyl-triazine

Two new transition metal coordination complexes, ([MnO(nda)](H{sub 2}dmt)(H{sub 2}O)){sub n} (1), [Ag{sub 5}(nda){sub 2.5}(dmt)]{sub n} (2), (H{sub 2}nda=naphthalene-1,4-dicarboxylic acid, dmt=2,4-diamine-6-methyl-1,3,5-triazine) have been hydrothermally synthesized by the reactions of H{sub 2}nda and dmt with the homologous MnCl{sub 2}·4H{sub 2}O and AgNO{sub 3}, respectively, and characterized by single-crystal X-ray diffraction, IR spectra, elemental analysis, thermogravimetric analysis (TGA). The compound 1 exhibits a 3D network comprising 1D metal chain (MnO(CO{sub 2}){sub 2}){sub n} connected by the ligand nda{sup 2−}, featuring a four-connected uninodal diamond -like topology. In compound 2, it is firstly observed that decanuclear silver units as secondary building units to construct 3D network by the ligands dmt and nda{sup 2−}, with a rare 2-nodal (3,8)-connected tfz-d topology ((4{sup 3}){sub 2}(4{sup 6}.6{sup 18}.8{sup 4})). The interactions within each Mn(II)—Mn(II) pair of compound 1 are antiferromagnetic (g=2.07, J=−1.42(1) cm{sup −1}, zj′=−0.73(2) cm{sup −1}). In addition, compound 2 exhibits photoluminescent property at about 472 nm (λ{sub ex}=394 nm). - Graphical abstract: Two new transition metal coordination complexes 1–2 have been hydrothermally synthesized and characterized by single-crystal X-ray diffraction, IR spectra, elemental analysis thermogravimetric analysis (TGA). Highlights: • The compound 1 exhibits a 3D network with four-connected uninodal diamond-like topology. • The first 3D network of 2 with a rare tfz-d topology consists of decanuclear silver clusters as secondary building units. • The magnetic measurement indicates the compound 1 shows antiferromagnetic interactions. • The photoluminescent property of 2 has been measured.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2017

Crystal structure, homogeneity range and electronic structure of rhombohedral γ-Mn 5 Al 8

Here, the γ-region of the Mn–Al phase diagram between 45 and 70 at.% Al was re-investigated by a combination of powder and single crystal X-ray diffraction as well as EDS analysis to establish the distribution of Mn and Al atoms. Single crystals of γ-Mn 5–x Al 8+x were grown using Sn-flux at 650 °C. The crystal structure, atomic coordinates and site occupancy parameters of γ-Mn 5–x Al 8+x phases were refined from single crystal X-ray data. The γ-Mn 5-x Al 8+x phase adopts the rhombohedral Cr 5 Al 8 -type structure rather than a cubic γ-brass structure. The refined compositions from two crystals extracted from the Al-rich and Mn-rich sides are, respectively, Mn 4.76 Al 8.24(2) (I) and Mn 6.32 Al 6.68(2) (II). The structure was refined in the acentric R3m space group (No.160, Z=6), in order to compare with other reported rhombohedral γ-brasses. In addition, according to X-ray powder diffraction analysis, at the Al-rich side the γ-phase coexists with LT–Mn 4 Al 11 and, at the Mn-rich side, with a hitherto unknown phase. The refined lattice parameters from powder patterns fall in the range a=12.6814(7)–12.6012(5) Å and c=7.9444(2)–7.9311(2) Å from Al-rich to Mn-rich loadings, and the corresponding rhombohedral angles distorted from a pseudo-cubic cell were found to be 89.1(1)°–88.9(1)°. Magnetic susceptibility and magnetization studies of Mn 4.92 Al 8.08(2) are consistent with moment bearing Mn and suggest a spin glass state below 27 K. Tight-binding electronic structure calculations (LMTO-ASA with LSDA) showed that the calculated Fermi level for γ-“Mn 5 Al 8 ” falls within a pseudogap of the density of states, a result which is in accordance with a Hume-Rothery stabilization mechanism γ-brass type phases.

36 MATERIALS SCIENCE↗
DOE OSTI2017

Experimental Investigation of Cellulose/Silver Nanocomposites Using In Situ Generation Method

Cellulose gel films were prepared by regeneration process using pre-cooled aq.(8 wt% LiOH + 15 wt% urea) mixture as solvent and ethyl alcohol as non solvent. The Terminus cattapa leaf extract diffused wet cellulose films were then dipped in 1–5 mM aq.AgNO{sub 3} solutions to allow in situ generation of silver nanoparticles (AgNPs). Besides the in situ generation, some AgNPs were also formed outside the wet films in the solution. The AgNPs formed outside the films were observed under transmission electron microscope and scanning electron microscope. The nanocomposite films were also characterized by Fourier transform infrared spectroscopy, X-ray diffraction and thermogravimetric analysis and tensile test. The thermal stability of the composite films was lower than that of the matrix up to a temperature of ~300 °C and afterwards showed a reverse trend. The tensile strength of the nanocomposite films was found to be higher than the matrix but decreased with increasing concentration of aq.AgNO{sub 3}. The cellulose/AgNPs composite films showed good antibacterial activity against E. coli (gram positive) and Bacillus sp. (gram negative). Based on the aforementioned properties, the cellulose/AgNPs composite films can be considered for antibacterial packaging and medical applications.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2013

Effect of TiO{sub 2} additives to the sintering of Y{sub 2}O{sub 3}

The effect of sintering additive on the microstructure development of yttrium oxide was investigated. Different combinations of yttrium oxide with TiO{sub 2} were used as x-ray diffraction, differential thermal analysis (DTA) were sintering additive. The investigated and microstructure of resulting compacts were characterized by, using scanning electron microscopy, porosity and sintering density for all compacting samples sintered at different sintering temperature under static air.

36 MATERIALS SCIENCE↗
DOE OSTI2013

AgSb(S{sub x}Se{sub 1−x}){sub 2} thin films for solar cell applications

Highlights: ► AgSb(S{sub x}Se{sub 1−x}){sub 2} thin films were formed by heating Na{sub 2}SeSO{sub 3} dipped Sb{sub 2}S{sub 3}/Ag layers. ► S/Se ratio was varied by changing the dipping time in Na{sub 2}SeSO{sub 3} solution. ► Characterized the films using XRD, XPS, SEM, Optical and electrical measurements. ► Band gap engineering of 1−1.1 eV for x = 0.51 and 0.52 respectively. ► PV Glass/FTO/CdS/AgSb(S{sub x}Se{sub 1−x}){sub 2}/C were prepared showing V{sub oc} = 410 mV, J{sub sc} = 5.7 mA/cm{sup 2}. - Abstract: Silver antimony sulfoselenide (AgSb(S{sub x}Se{sub 1−x}){sub 2}) thin films were prepared by heating glass/Sb{sub 2}S{sub 3}/Ag layers after selenization using sodium selenosulphate solution. First, Sb{sub 2}S{sub 3} thin films were deposited on glass substrates from a chemical bath containing SbCl{sub 3} and Na{sub 2}S{sub 2}O{sub 3}. Then Ag thin films were thermally evaporated onto glass/Sb{sub 2}S{sub 3}, followed by selenization by dipping in an acidic solution of Na{sub 2}SeSO{sub 3}. The duration of selenium dipping was varied as 30 min and 2 h. The heating condition was at 350 °C for 1 h in vacuum. Analysis of X-ray diffraction pattern of the thin films formed after heating showed the formation of AgSb(S{sub x}Se{sub 1−x}){sub 2}. Morphology and elemental analysis were done by scanning electron microscopy and energy dispersive X-ray detection. Depth profile of composition of the thin films was performed by X-ray Photoelectron Spectroscopy. The spectral study showed the presence of Ag, Sb, S, and Se, and the corresponding binding energy analysis confirmed the formation of AgSb(S{sub x}Se{sub 1−x}){sub 2}. Photovoltaic structures (PV) were prepared using AgSb(S{sub x}Se{sub 1−x}){sub 2} thin films as absorber and CdS thin films as window layers on FTO coated glass substrates. The PV structures were heated at 60–80 °C in air for 1 h to improve ohmic contact. Analysis of J–V characteristics of the PV structures showed V{sub oc} from 230 to 490 mV and J{sub sc} 0.28 to 5.70 mA/cm{sup 2}, under illumination of AM1.5 radiation using a solar simulator.

36 MATERIALS SCIENCE↗
DOE OSTI2019

In Situ Cs and H Exchange into Gaidonnayite and Proposed Mechanisms of Ion Diffusion

Here, the microporous mineral gaidonnayite Na 2 ZrSi 3 O 9 ·2H 2 O was studied to better understand its ion-exchange mechanisms, specifically for Cs + and H + ions. In situ Raman spectroscopy, in situ X-ray diffraction (XRD), simultaneous thermogravimetric analysis and differential scanning calorimetry (TGA/DSC), and in situ X-ray fluorescence were used to determine the exchange processes involved. The Raman spectra contain strong peaks that can be attributed to the vibrational modes for the 3MR symmetric stretch at 500 cm –1 , Si–O–Zr–O chain stretches at 938 cm –1 , and Si–O stretching in the 1000–1100 cm –1 range. The most prominent Raman shift during ion exchange is found near the 520 cm –1 peak, which corresponds to distortions of the 3MR substructure of gaidonnayite. In all instances of this study, the 3MR exhibited the highest amount of distortion during ion exchange, and the evolution of this distortion is compared to unit-cell changes as measured from XRD data and elemental changes via XRF. The correlations between the Raman, XRD, and XRF data show rapid deformation of the 3MR during the onset of H + ion exchange in the Na form of gaidonnayite. Even when unit-cell volume changes were small (<3 Å 3 ) as in the cases for Cs + into Na-gaidonnayite and Cs + into H-gaidonnayite, significant changes in the ≈520 cm –1 peak were measured. By comparing XRD data and Raman data, and verifying the cation uptake by XRF, we were able to identify and confirm conformational changes and distortions in the crystal structure before, during, and after Cs + and H + exchange. Finally, Cs exchange occurred the fastest and with the greatest capacity when starting in the H-form at room temperature, and at elevated temperatures when starting in the Na-form.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2014

Application of E{sub h}-pH diagram for room temperature precipitation of zinc stannate microcubes in an aqueous media

Graphical abstract: - Highlights: • One pot aqueous synthesis of zinc stannate (ZnSnO{sub 3}) particles at low temperature. • Synthesis designed with the assistance of potential-pH diagram. • ZnSnO{sub 3} estimated to be stable between pH 8 and 12 was used for synthesis of the particles. • ZnSnO{sub 3}·3H{sub 2}O were formed during the precipitation of zinc stannate. - Abstract: Potential-pH diagram assisted-design for controlled precipitation is an attractive method to obtain engineered binary and ternary oxide particles. Aqueous synthesis conditions of zinc stannate (ZnSnO{sub 3}) particles at low temperature were formulated with the assistance of potential-pH diagram. The pH of a solution containing stoichiometric amounts of Zn{sup 2+} and Sn{sup 4+} was controlled for the precipitation in a one pot synthesis step at room temperature (25 °C). The effect of the concentration of the reactants on the particle size was studied by varying the concentration of the precursor (Zn{sup 2+} + Sn{sup 4+}) solution. Scanning electron micrographs show that the particles are monodispersed micron sized cubes formed by the self-organization of nano-sized crystallites. The obtained microcubes characterized by X-ray Diffraction and thermo gravimetric analysis (TGA) show that the particles are in ZnSnO{sub 3}·3H{sub 2}O form.

36 MATERIALS SCIENCE↗
DOE OSTI2014

Synthesis and characterization of pharmaceutical surfactant templated mesoporous silica: Its application to controlled delivery of duloxetine

Graphical abstract: - Highlights: • Usefulness of dual pharmaceutical surfactants in silica synthesis was evaluated. • Effects of concentration of secondary template (Tween-40) were studied. • Effects of fixed solvothermal condition on mesostructure formation were studied. • Duloxetine drug loading capability was studied. • Sustained release of duloxetine was evaluated. - Abstract: A new group of mesoporous silica nanoparticles (MSNs) were synthesized using combination pharmaceutical surfactants, Triton X-100 and Tween-40 as template and loaded with duloxetine hydrochloride (DX), for improving the sustained release of DX and patterns with high drug loading. Agglomerated spherical silica MSNs were synthesized by sol–gel and solvothermal methods. The calcined and drug loaded MSNs were characterized using X-ray diffraction (XRD), Braunner–Emmett–Teller (BET), thermogravimetric analysis (TGA), Fourier-transform infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM), differential scanning calorimetry (DSC), diffuse reflectance ultraviolet–visible (DRS-UV–vis) spectroscopy. MSNs with high surface area and pore volume were selected and studied for their DX loading and release. The selected MSNs can accommodate a maximum of 34% DX within it. About 90% was released at 200 h and hence, the synthesized MSNs were capable of engulfing DX and sustain its release. Further form the Ritger and Peppas, Higuchi model for mechanism drug release from all the MSN matrices follows anomalous transport or Non-Fickian diffusion with the ‘r’ and ‘n’ value 0.9 and 0.45 < n < 1, respectively. So, from this study it could be concluded that the MSNs synthesized using pharmaceutical templates were better choice of reservoir for the controlled delivery of drug which requires sustained release.

36 MATERIALS SCIENCE↗