Effect of Processing Parameters on the Morphology, Particulate, and Superconducting Properties of Electrospun YBCO Nanostructures

Superconductivity in nanostructured ceramics offers significant advantages over the conventional coarse-grained materials in view of miniaturization of superconducting electronic devices. In this paper, we report the formation of four morphologies of superconducting YBa2Cu3O7-δ (YBCO) nanostructures by electrospinning technique using polymeric polyvinyl pyrrolidone (PVP) solutions of different molecular weight and altering the total content of the metallic precursors. The morphologies prepared using this strategy are nanorods (NRs), nanogarlands (NGs), nanohierarchical (NH), and nanoparticles (NPs). Alternating current susceptibility measurements showed high critical temperatures (TC ~90 K) for the NH YBCO synthesized using PVP of the lowest molecular weight; whereas the YBCO NRs synthesized using a higher molecular weight polymer showed the lowest TC (82 K). A relationship between the particulate properties and TC was also observed – the lower is the pore size the higher is the TC. The YBCO NGs showed the highest specific surface area (7.06 m2/g) with intermediate TC (88 K). Electrospinning process appears an effective and controllable technique to produce different nanomorphologies with intrinsic properties suitable for practical applications.

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Structural and Thermophysical Studies of Composite Na-Cobaltite Electrospun Nanofibers

Journal of Materials ◽

10.1155/2015/838957 ◽

2015 ◽

Vol 2015 ◽

pp. 1-8 ◽

Cited By ~ 1

Author(s):

Fatima-tuz-Zahra ◽

M. Anis-ur-Rehman

Keyword(s):

Thermal Conductivity ◽

Flow Rate ◽

Sol Gel ◽

Electrospun Nanofibers ◽

Processing Parameters ◽

Electrospinning Process ◽

X Ray Diffraction ◽

Scanning Calorimetry ◽

Electrospinning Technique ◽

Energy Applications

Polymeric nanofibers have been produced in the last few years by electrospinning of polymer solutions. Polyvinyl alcohol (PVA) was the selected polymer for the preparation of nanofibers. Processing parameters like flow rate, needle gauge, needle to collector distance, and molarity of the solution have been optimized during electrospinning process. Sol-gel method has been used for the preparation of thermoelectric cobaltite nanoparticles having composition NaCoO2. Sol-gel combined electrospinning technique was used to prepare the composites of the NaCoO2 with PVA nanofibers. X-ray diffraction (XRD), thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC) have been used for the structural analysis of the prepared samples. Scanning electron microscopy (SEM) was used to observe the morphology of the prepared fibers. SEM micrographs showed that, by increasing the flow rate, diameter of the fibers increased from 185 nm to 200 nm. Two-probe method and Advantageous Transient Plane Source (ATPS) were used to study the electrical and thermal transport properties, respectively. Thermal conductivity and electrical conductivity showed a direct dependence on temperature. It was observed that particles, sample has lower thermal conductivity (0.610 W/m-K) as compared to that of composite nanofibers (1.129 W/m-K). The measurements reported are novel and are useful for energy applications.

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Mechanical Behavior of Hydroxyapatite-Chitosan Composite: Effect of Processing Parameters

Minerals ◽

10.3390/min11020213 ◽

2021 ◽

Vol 11 (2) ◽

pp. 213

Author(s):

Hamid Ait Said ◽

Hassan Noukrati ◽

Hicham Ben Youcef ◽

Ayoub Bayoussef ◽

Hassane Oudadesse ◽

...

Keyword(s):

Molecular Weight ◽

Compressive Strength ◽

Mechanical Strength ◽

Bone Repair ◽

Mechanical Stability ◽

Three Dimensional ◽

Processing Parameters ◽

Composite Effect ◽

Solid Liquid ◽

The Impact

Three-dimensional hydroxyapatite-chitosan (HA-CS) composites were formulated via solid-liquid technic and freeze-drying. The prepared composites had an apatitic nature, which was demonstrated by X-ray diffraction and Infrared spectroscopy analyses. The impact of the solid/liquid (S/L) ratio and the content and the molecular weight of the polymer on the composite mechanical strength was investigated. An increase in the S/L ratio from 0.5 to 1 resulted in an increase in the compressive strength for HA-CSL (CS low molecular weight: CSL) from 0.08 ± 0.02 to 1.95 ± 0.39 MPa and from 0.3 ± 0.06 to 2.40 ± 0.51 MPa for the HA-CSM (CS medium molecular weight: CSM). Moreover, the increase in the amount (1 to 5 wt%) and the molecular weight of the polymer increased the mechanical strength of the composite. The highest compressive strength value (up to 2.40 ± 0.51 MPa) was obtained for HA-CSM (5 wt% of CS) formulated at an S/L of 1. The dissolution tests of the HA-CS composites confirmed their cohesion and mechanical stability in an aqueous solution. Both polymer and apatite are assumed to work together, giving the synergism needed to make effective cylindrical composites, and could serve as a promising candidate for bone repair in the orthopedic field.

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Poly(lactic Acid): A Versatile Biobased Polymer for the Future with Multifunctional Properties—From Monomer Synthesis, Polymerization Techniques and Molecular Weight Increase to PLA Applications

Polymers ◽

10.3390/polym13111822 ◽

2021 ◽

Vol 13 (11) ◽

pp. 1822

Author(s):

Evangelia Balla ◽

Vasileios Daniilidis ◽

Georgia Karlioti ◽

Theocharis Kalamas ◽

Myrika Stefanidou ◽

...

Keyword(s):

Molecular Weight ◽

Lactic Acid ◽

Chain Extension ◽

Poly Lactic Acid ◽

Plastic Pollution ◽

Practical Applications ◽

Decomposition Reactions ◽

Melt Polycondensation ◽

Polymerization Conditions ◽

Molecular Weight Increase

Environmental problems, such as global warming and plastic pollution have forced researchers to investigate alternatives for conventional plastics. Poly(lactic acid) (PLA), one of the well-known eco-friendly biodegradables and biobased polyesters, has been studied extensively and is considered to be a promising substitute to petroleum-based polymers. This review gives an inclusive overview of the current research of lactic acid and lactide dimer techniques along with the production of PLA from its monomers. Melt polycondensation as well as ring opening polymerization techniques are discussed, and the effect of various catalysts and polymerization conditions is thoroughly presented. Reaction mechanisms are also reviewed. However, due to the competitive decomposition reactions, in the most cases low or medium molecular weight (MW) of PLA, not exceeding 20,000–50,000 g/mol, are prepared. For this reason, additional procedures such as solid state polycondensation (SSP) and chain extension (CE) reaching MW ranging from 80,000 up to 250,000 g/mol are extensively investigated here. Lastly, numerous practical applications of PLA in various fields of industry, technical challenges and limitations of PLA use as well as its future perspectives are also reported in this review.

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Performance-tuning of PVA-based gel electrolytes by acid/PVA ratio and PVA molecular weight

SN Applied Sciences ◽

10.1007/s42452-021-04182-7 ◽

2021 ◽

Vol 3 (3) ◽

Author(s):

Saeideh Alipoori ◽

M. M. Torkzadeh ◽

Saeedeh Mazinani ◽

Seyed Hamed Aboutalebi ◽

Farhad Sharif

Keyword(s):

Molecular Weight ◽

Ionic Conductivity ◽

Charge Carrier Concentration ◽

Fine Tuning ◽

Performance Tuning ◽

Practical Applications ◽

High Performing ◽

Flexible Devices ◽

Gel Electrolytes ◽

Ion Conducting

AbstractThe significant breakthroughs of flexible gel electrolytes have attracted extensive attention in modern wearable electronic gadgets. The lack of all-around high-performing gels limits the advantages of such devices for practical applications. To this end, developing a multi-functional gel architecture with superior ionic conductivity while enjoying good mechanical flexibility is a bottleneck to overcome. Herein, an architecturally engineered gel, based on PVA and H3PO4 with different molecular weights of PVA for various PVA/H3PO4 ratios, was developed. The results show the dependence of ionic conductivity on molecular weight and also charge carrier concentration. Consequently, fine-tuning of PVA-based gels through a simple yet systematic and well-regulated strategy to achieve highly ion-conducting gels, with the highest ionic conductivity of 14.75 ± 1.39 mS cm-1 have been made to fulfill the requirement of flexible devices. More importantly, gel electrolytes possess good mechanical robustness while exhibiting high-elasticity (%766.66 ± 59.73), making it an appropriate candidate for flexible devices.

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Design of Aerogels, Cryogels and Xerogels of Alginate: Effect of Molecular Weight, Gelation Conditions and Drying Method on Particles’ Micromeritics

Molecules ◽

10.3390/molecules24061049 ◽

2019 ◽

Vol 24 (6) ◽

pp. 1049 ◽

Cited By ~ 11

Author(s):

Rosalía Rodríguez-Dorado ◽

Clara López-Iglesias ◽

Carlos García-González ◽

Giulia Auriemma ◽

Rita Aquino ◽

...

Keyword(s):

Molecular Weight ◽

Physicochemical Properties ◽

Textural Properties ◽

Supercritical Drying ◽

Processing Parameters ◽

Storage Conditions ◽

Drying Methods ◽

Drying Method ◽

Molecular Weights ◽

Nanostructured Particles

Processing and shaping of dried gels are of interest in several fields like alginate aerogel beads used as highly porous and nanostructured particles in biomedical applications. The physicochemical properties of the alginate source, the solvent used in the gelation solution and the gel drying method are key parameters influencing the characteristics of the resulting dried gels. In this work, dried gel beads in the form of xerogels, cryogels or aerogels were prepared from alginates of different molecular weights (120 and 180 kDa) and concentrations (1.25, 1.50, 2.0 and 2.25% (w/v)) using different gelation conditions (aqueous and ethanolic CaCl2 solutions) and drying methods (supercritical drying, freeze-drying and oven drying) to obtain particles with a broad range of physicochemical and textural properties. The stability of physicochemical properties of alginate aerogels under storage conditions of 25 °C and 65% relative humidity (ICH-climatic zone II) during 1 and 3 months was studied. Results showed significant effects of the studied processing parameters on the resulting alginate dried gel properties. Stability studies showed small variations in aerogels weight and specific surface area after 3 months of storage, especially, in the case of aerogels produced with medium molecular weight alginate.

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ELECTROSPINNING OF BIOMATERIALS AND THEIR APPLICATIONS IN TISSUE ENGINEERING

Nano LIFE ◽

10.1142/s1793984412300105 ◽

2012 ◽

Vol 02 (04) ◽

pp. 1230010 ◽

Cited By ~ 2

Author(s):

JEN-CHIEH WU ◽

H. PETER LORENZ

Keyword(s):

Tissue Engineering ◽

Electrospinning Process ◽

Polymer Fibers ◽

Nanometer Scale ◽

High Porosity ◽

Electrospinning Technique ◽

Engineering Research ◽

Fibrous Scaffolds ◽

Surface Areas ◽

Tissue Engineering Research

Electrospinning is a process for generating micrometer or nanometer scale polymer fibers with large surface areas and high porosity. For tissue engineering research, the electrospinning technique provides a quick way to fabricate fibrous scaffolds with dimensions comparable to the extracellular matrix (ECM). A variety of materials can be used in the electrospinning process, including natural biomaterials as well as synthetic polymers. The natural biomaterials have advantages such as excellent biocompatibility and biodegradability, which can be more suitable for making biomimic scaffolds. In the last two decades, there have been growing numbers of studies of biomaterial fibrous scaffolds using the electrospinning process. In this review, we will discuss biomaterials in the electrospinning process and their applications in tissue engineering.

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A Concept of a “Virtual Production Line” Produced by Integrating Databases and Models of Materials

MRS Bulletin ◽

10.1557/s0883769400037507 ◽

1993 ◽

Vol 18 (7) ◽

pp. 29-34 ◽

Cited By ~ 4

Author(s):

Shuichi Iwata

Keyword(s):

Production Line ◽

Ad Hoc ◽

Intelligent System ◽

Processing Parameters ◽

Alloy Development ◽

Bottom Up ◽

Vast Number ◽

Practical Applications ◽

Virtual Production ◽

Almost All

One of the requirements for an intelligent system is to construct a virtual reality in the computer. For materials development, the “reality” is a laboratory or a production line used to improve some aspect of a material by changing its composition, processing parameters, service conditions, etc. In the case of information in libraries, the reality is a search that uses a thesaurus and bibliographic (fact) databases. The greatest barrier faced by users of materials information is that of accessing necessary information through both a librarian's view and a scientific/technological expert's view. One of the objectives of a virtual production line is to reduce this barrier through user-friendly interfaces.In designing materials, two typical approaches are combined to solve a given problem. The first is a top-down approach, in which a number of requirements are resolved to a set of possible and practical solutions for satisfying these requirements to a certain level. Almost all alloy development has followed such an approach. The second approach is a bottom-up approach, where different materials properties are described on the basis of underlying theories, preferably using first principles and fundamental data. But the vast number of possible materials makes the bottom-up approach unrealistic on its own. Instead, semi-empirical approaches are needed to bridge the gap between ad hoc data sets for practical applications and results produced by the bottom-up approach using fundamental data and first-principle calculations.

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Structure-Property Relationship of Dodecylbenzenesulfonic Acid Doped Polyaniline

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.721.199 ◽

2013 ◽

Vol 721 ◽

pp. 199-205 ◽

Cited By ~ 1

Author(s):

Ying Liu ◽

Qi Wen ◽

Jia Li Guan ◽

Shi Jie Zhao ◽

Qi Xing Hu ◽

...

Keyword(s):

Molecular Weight ◽

Ammonium Persulfate ◽

Degree Of Crystallinity ◽

Structure Property ◽

X Ray Diffraction ◽

Electrospinning Technique ◽

Dodecylbenzenesulfonic Acid ◽

Molar Ratios ◽

Liquid Crystal Property ◽

Relationship Of

Dodecylbenzenesulfonic acid (DBSA) doped polypanilines (PANIs) were chemically synthesized in different molar ratios of aniline (An) to ammonium persulfate (APS) and An to DBSA. The microstructures of these PANIs were investigated by means of scanning electron microscope (SEM), X-ray diffraction (XRD), and Fourier Transform Infrared (FTIR). UV-Vis spectrometer, semiconductor parameter analyzer, ubbelohde viscometer and electrospinning technique were used to characterize the optical, electrical properties, viscosity and solubility of these PANIs. The results show that the molar rations of An to APS and An to DBSA had strong effect on the microstructure, molecular weight, degree of crystallinity, optical property, solubility and conductivity of obtained DBSA doped PANI. With the increase of the molar ratios of An to APS and An to DBSA, the conductivities and molecular weight of DBSA doped PANIs decreased, while the degree of crystallinity and solubility of DBSA doped PANIs increased. The DBSA doped PANI could dissolve in dichloromethane or HFIP and could be fabricated short fibers by electrospinning. Moreover, the solution of DBSA doped PANIs in concentrated sulphuric acid showed liquid crystal property.

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