Polypyrrole- and polyaniline-surface modified nanosilica as quasi-solid state electrolyte ingredients for dye-sensitized solar cells

Polyurethane nanocomposites were formulated to entrap liquid electrolyte for quasi-solid-state electrolytes (QSEs) in dyesensitized solar cells (DSSCs). Polypyrrole- and polyaniline-surface engineered silica nanoparticles (NPs) were each incorporated to form polyurethane nanocomposites. The formation of nanosilica and its surface modification, as well as the size, aggregation, and isoelectric point of the synthesized NPs were analyzed using ATR-FTIR, TEM, and DLS. In addition, the filler (silica)–matrix (polyurethane) interaction, NP distribution, surface morphology, surface porosity, and the thermal stability of the polyurethane nanocomposite were analyzed by ATR-FTIR, transmitted and reflected light microscopes, ImageJ, and TGA. The polymer matrix absorptivity, conductivity, and ion diffusion of the polyurethane nanocomposite-based QSE was investigated by using a digital analytical balance, the AC impedance method, and the cyclic voltammetry. Lastly, all of the formulated QSEs were applied in DSSCs and their photovoltaic performance was measured. The QSE based on polyaniline surface engineered nanosilica demonstrated the highest light-to-energy conversion efficiency, namely 3.10%, with an open circuit voltage of 715 mV, a short circuit current of 3.88 mA cm−2, and a fill factor of 0.67. A reasonable lifespan stability was also found for 100 min illumination and a corresponding efficiency of 2.47% obtained

Development And Properties Of Chemically Cross Linked Rubber Foams.

Kesan penggunaan natrium hidrogen karbonat (NaHC03) sebagai agen peniupan dalam pengeluaran atau pembentukan span getah berangkaisilang secara kimia berasaskan SMR (getah semuiajadi) dan EPDivi (getah eiiiena propilena telah dipertimbangkan. Terdapat tiga teknik pemprosesan digunakan dengan parameter dan keadaan pemprosesan yang berbeza

Techniques And Parameters Investigation On Crosslinked Rubber Foam Formations.

Single Suge, Heat Transfer and Heat and Chill techniques were applied n determine suitablc methods for crosslinked rubber foam formation

Synthesis of organo-functionalized nanosilica via a co-condensation modification using γ-aminopropyltriethoxysilane (APTES)

An easy and swift pathway in preparation of organo-functionalized silica in nanosize range with amine-terminated group via co-condensation method is reported. The process is a self-catalyzed reaction by amine group of organosilane without the addition of ammonia as a catalyst at room temperature. A modified nanosilica with particle size of ∼60nm, highly monodispersed and low aggregation was successfully produced. The use of methanol as a solvent leads to the increase in particle size. CHN, FTIR and NMR analyses revealed the presence of organo-functional group in the bulk and at the surface of the silica particles

Size-dependent physicochemical and optical properties of silica nanoparticles

The size-dependent physicochemical and optical properties of silica nanoparticles have been studied. Significant increase in the specific surface area (SSA), concentration of silanol groups (δOH) and apparent density (Da) were observed as the particle size reduced from ∼130 to ∼7 nm. The decrease in the silanol number (αOH) and Si–O–Si bond angle in smaller particle size suggest that the silica structure, especially the surface has been significantly altered at nanoscale. This finding is supported by the presence of defect sites such as E′ centers and oxygen deficient centers (OCD). The stability of E′ centers (UV–vis analysis) increase linearly with the increase in particle size. The increase in the intensity of blue and green bands (PL analysis) with the decrease in the particle size are attributed to the higher silanol concentration and increased in the number of self-trapped exciton (STE)/OCD, respectively. The green band was blue-shifted with the decrease in the particle size. Overall, the silica nanoparticles have shown distinctive properties relative to the bulk silica

Crosslinking of polyolefin foams: I. Effect of triallyl cyanurate on dicumyl peroxide crosslinking of low-density polyethylene

This study investigates peroxide crosslinking of two low-density polyethylene grades of similar number average molecular weight but differing molecular weight distribution. At gel contents typically associated with dicumyl peroxide (DCP) crosslinked foams, crosslinking and melt tensile properties of the solid matrix, foaming behaviour and foam properties were not significantly different. The main work compared the effects of crosslinking systems based on DCP alone and DCP with the polyfunctional monomer, triallylcyanurate (TAC). The presence of TAC allowed specific gel contents to be achieved at significantly reduced DCP concentrations compared with DCP alone. It was also determined that cost-effective use of TAC was limited to approximately 0.5 parts per hundred resin. When comparing results of solid and foamed samples of identical gel content, the presence of TAC significantly increases the melt modulus and reduces extensibility of the solid matrix compared with DCP alone and promotes a higher nucleation density in foam. This is considered to be due to a higher crosslink density in the network fraction which introduces complications in prediction of foaming behaviour if gel content alone is considered

Synthesis of silica nanoparticles by modified sol–gel process: the effect of mixing modes of the reactants and drying techniques

A modified preparation of silica nanoparticles via sol–gel process was described. The ability to control the particle size and distribution was found highly dependent on mixing modes of the reactants and drying techniques. The mixture of tetraethoxysilane and ethanol followed by addition of water (Mode-A) produced monodispersed powder with an average particle size of 10.6 ± 1.40 nm with a narrow size distribution. The freeze drying technique (FD) further improved the quality of powder. In addition, the freeze dried samples have shown unique TGA decomposition steps which might be related to the well-defined structure of silica nanoparticles as compared to the heat dried samples. DSC analysis showed that FD preserved the silica surface with low shrinkage and generated remarkably well-order, narrow and bigger pore size and pore volume and also large endothermic enthalpies (ΔH FD = −688 J g−1 vs. ΔH HD = −617 J g−1) that lead to easy escape of physically adsorbed water from the pore at lower temperature

Synthesis of Hydroxyapatite/Bioglass Composite Nanopowder Using Design of Experiments

Composite scaffolds of hydroxyapatite (HAp) nanoparticles and bioactive glass (BG) were applied as an appropriate selection for bone tissue engineering. To this end, HAp/BG composite was synthesized by a hydrothermal method using Design of Experiments (DOE) with a combined mixture–process factor design for the first time. The input variables were hydrothermal temperature at three levels (i.e., 100, 140, 180 °C) as a process factor and two mixture components in three ratios (i.e., HAp 90, 70, 50; BG 50, 30, 10). The degree of crystallinity and crystal size in the composite were the output variables. XRD showed that only a small fraction of BG was crystallized and that a wollastonite phase was produced. The XRD results also revealed that incorporation of Si into the HAp structure inhibited HAp crystal growth and restricted its crystallization. The FTIR results also showed that the intensity of the hydroxyl peak decreased with the addition of silicon into the HAp structure. DOE results showed that the weight ratio of the components strongly influenced the crystal size and crystallinity. SEM and FTIR results identified the greatest bioactivity and apatite layer formation in the Si-HAp sample with an HAp70/BG30 ratio after 14 days immersion in simulated body fluid (SBF) solution, as compared to other ratios and HAp alone. Therefore, the combination of HAp and BG was able to yield a HAp/BG composite with significant bioactivity

Review on metallic and plastic flexible dye sensitized solar cell

Dye sensitized solar cells (DSSCs) are a promising alternative for the development of a new generation of photovoltaic devices. DSSCs have promoted intense research due to their low cost and eco-friendly advantage over conventional silicon-based crystalline solar cells. In recent years, lightweight flexible types of DSSCs have attracted much intention because of drastic reduction in production cost and more extensive application. The substrate that used as electrode of the DSSCs has a dominant impact on the methods and materials that can be applied to the cell and consequently on the resulting performance of DSSCs. Furthermore, the substrates influence significantly the stability of the device. Although the power conversion efficiency still low compared to traditional glass based DSSCs, flexible DSSCs still have potential to be the most efficient and easily implemented technology

Electroless plating of moisture-curable polyurethane undercoating films

The compatibility of using moisture-curable polyurethane (MCPU) system as a thin undercoating layer with electroless plating process was evaluated. The characteristics of the MCPU before and after chemical etching treatment were analyzed using atomic force microscope (AFM), scanning electrode microscope (SEM), contact-angle measurements, and (Fourier-Transform Infrared) FTIR spectroscopy. We found that surface morphology and roughness of the MCPU is affected by curing period and etching times. A proper combination of curing period and etching times are critical for obtaining a fully metallized surface. All MCPU samples that were etched for 15 min show poor plating performance due to surface damage caused by mild etching treatment. A standard pull-off testing method (ASTM 4541) was used to evaluate the adhesion strength of nickel–MCPU. Only samples that were postcured for 4 days show influence of surface roughness on adhesion strength. On average, samples that were postcured for 7 days before electroless plating showed better adhesion of nickel–MCPU compared with samples that were postcured for 2 or 4 days. The results show that MCPU system can be used as a thin undercoating layer for electroless plating. It also offers smooth metal–polymer interface and therefore has the potential to be exploited for use in many electroless plating applications including in the decorative such as ornaments and display items and also in electronic industries