Synthesis of silicalite-poly(furfuryl alcohol) composite membranes for oxygen enrichment from air

An improved approach to assemble ultrathin and thickness-tunable polypyrrole (PPy) films onto multiwall carbon nanotubes (MWCNTs) has been investigated. A facile procedure is demonstrated for controlling the morphology and thickness of PPy film by adding ethanol in the reaction system and a possible mechanism of the coating formation process is proposed. The coated PPy films can be easily tuned by adding ethanol and adjusting a mass ratio of pyrrole to MWCNTs. Moreover, the thickness of PPy significantly influences the electronic conductivity and capacitive behavior of the PPy/MWCNT composites. The method may provide a facile strategy for tailoring the polymer coating on carbon nanotubes (CNTs) for carbon-based device applications.     

Study of polycarbonate–polystyrene interfaces using scanning transmission electron microscopy spectrum imaging (STEM-SI)

Polymer blends are important for both commercial utility and scientific understanding. The degree of interfacial mixing in polymer blends is important since it influences the blends' mechanical properties. Understanding bulk properties in multiphase polymeric materials requires knowledge of the interfacial properties of the materials. The characterization of the interface, in terms of its width and composition profile, provides insight about the bulk behaviour of the material. Chemical microscopy through electron energy-loss spectroscopy (EELS) in a transmission electron microscope is gaining popularity to characterize narrow polymer–polymer interfaces. In this work, we show how scanning transmission electron microscopy spectrum imaging, a spatially resolved energy-loss spectroscopy, can be employed to calculate the interfacial width in a pair of immiscible polymers, taking a polycarbonate–polystyrene (PC-PS) bilayer as an example. By mapping peaks unique to each of the blend constituents at several points across the interface, we show how the interfacial profile concentrations can be determined. With this method we calculated the interfacial width in the PC-PS bilayer sample to be approximately 32 nm, even utilizing low resolution spectrometers, which are more widely available. Using the technique described with higher resolution EELS instruments having a better signal-to-noise ratio, a higher spatial resolution can be achieved. Using EELS chemical fingerprints of polymers that have been developed earlier, the technique presented here has the potential for effective visualization and morphological measurements of phase-differentiated polymer blends. This paper is an attempt to enable a new user to characterize polymer–polymer interfaces using chemical microscopy. © 2022 Society of Industrial Chemistry.     

PVA-based hydrogels for tissue engineering: A review

Poly (vinyl alcohol) (PVA) is a hydrophilic polymer with excellent biocompatibility and has been applied in various biomedical areas due to its favorable properties. PVA-based hydrogels have been recognized as promising biomaterials and suitable candidates for tissue engineering applications and can be manipulated to act various critical roles. However, due to some disadvantages (i.e., lack of cell-adhesive property), they needs further modification for desired and targeted applications. This review highlights recent progress in the design and fabrication of PVA-based hydrogels, including crosslinking and processing techniques. Finally, major challenges and future perspectives in tissue engineering are briefly discussed.     

Sugarcane bagasse and leaves: foreseeable biomass of biofuel and bio‐products

Sugarcane is among the principal agricultural crops cultivated in tropical countries. The annual world production of sugarcane is ～1.6 billion tons, and it generates ～279 million metric tons (MMT) of biomass residues (bagasse and leaves). Sugarcane residues, particularly sugarcane bagasse (SB) and leaves (SL) have been explored for both biotechnological and non‐biotechnological applications. For the last three decades, SB and SL have been explored for use in lignocellulosic bioconversion, which offers opportunities for the economic utilization of residual substrates in the production of bioethanol and value‐added commercial products such as xylitol, specialty enzymes, organic acids, single‐cell protein, etc. However, there are still major technological and economic challenges to be addressed in the development of bio‐based commercial processes utilizing SB and SL as raw substrates. This article aims to explore SB and SL as cheaper sources of carbohydrates in the developing world for their industrial implications, their use in commercial products including commercial evaluation, and their potential to advance sustainable bio‐based fuel systems. Copyright © 2011 Society of Chemical Industry     

Triple-Networked Hybrid Hydrogels Reinforced with Montmorillonite Clay and Graphene Nanoplatelets for Soft and Hard Tissue Regeneration

Hydrogel is a three-dimensional (3D) soft and highly hydrophilic, polymeric network that can swell in water and imbibe a high amount of water or biological fluids. Hydrogels have been used widely in various biomedical applications. Hydrogel may provide a fluidic tissue-like 3D microenvironment by maintaining the original network for tissue engineering. However, their low mechanical performances limit their broad applicability in various functional tissues. This property causes substantial challenges in designing and preparing strong hydrogel networks. Therefore, we report the triple-networked hybrid hydrogel network with enhanced mechanical properties by incorporating dual-crosslinking and nanofillers (e.g., montmorillonite (MMT), graphene nanoplatelets (GNPs)). In this study, we prepared hybrid hydrogels composed of polyacrylamide, poly (vinyl alcohol), sodium alginate, MMT, and MMT/GNPs through dynamic crosslinking. The freeze-dried hybrid hydrogels showed good 3D porous architecture. The results exhibited a magnificent porous structure, interconnected pore-network surface morphology, enhanced mechanical properties, and cellular activity of hybrid hydrogels.     

Controlled environment vitrification system: An improved sample preparation technique

The controlled environment vitrification system (CEVS) permits cryofixation of hydrated biological and colloidal dispersions and aggregates from a temperature- and saturation-controlled environment. Otherwise, specimens prepared in an uncontrolled laboratory atmosphere are subject to evaporation and heat transfer, which may introduce artifacts caused by concentration, pH, ionic strength, and temperature changes. Moreover, it is difficult to fix and examine the microstructure of systems at temperatures other than ambient (e.g., biological systems at in vivo conditions and colloidal systems above room temperature). A system has been developed that ensures that a liquid or partially liquid specimen is maintained in its original state while it is being prepared before vitrification and, once prepared, is vitrified with little alteration of its microstructure. A controlled environment is provided within a chamber where temperature and chemical activity of volatile components can be controlled while the specimen is being prepared. The specimen grid is mounted on a plunger, and a synchronous shutter is opened almost simultaneously with the release of the plunger, so that the specimen is propelled abruptly through the shutter opening into a cryogenic bath. We describe the system and its use and illustrate the value of the technique with TEM micrographs of surfactant microstructures in which specimen preparation artifacts were avoided. We also discuss applications to other instruments like SEM, to other techniques like freeze-fracture, and to novel “on the grid” experiments that make it possible to freeze successive instants of dynamic processes such as membrane fusion, chemical reactions, and phase transitions.     

Experimental evaluation of sensitivity and non-linearity in polysilicon piezoresistive pressure sensors with different diaphragm sizes

MEMS-based piezoresistive pressure sensors are widely popular due to advantages such as small size, low cost, simple fabrication, and DC output. In this work, the design simulation, fabrication process, and characterization of four pressure sensors with square diaphragms of edge-length 1,060, 1,280, 1,480, and 1,690 µm are reported. Several design principles such as appropriate boundary condition, piezoresistor placement, and fracture stress are considered in the design phase. The sensors have novel shaped polysilicon piezoresistors and equal diaphragm thickness of 50 µm. The sensors are fabricated simultaneously by putting the different designs on the same mask set so that the best design can be determined after characterization. The uncompensated and unamplified output response of the different sensors are reported at three temperatures (?5, 25 and 55 °C). Out of the four sensors with different diaphragm sizes, the sensor with a diaphragm edge length of 1,280 μm is found to have optimum characteristics. For the diaphragm with edge-length of 1,280 µm, in the pressure range of 0–30 Bar, sensitivity of 3.35–3.73 mV/Bar, non-linearity of <0.3 %, and hysteresis of <0.1 % are obtained. The different sensors can be used in the specified pressure range for suitable applications.     

Moisture sorption isotherms of dietetic Rabri at different storage temperatures

Moisture sorption isotherms of dietetic Rabri were determined at 10, 25 and 37 °C over a water activity range of 0.113–0.868. Sorption isotherms at 37 °C were sigmoidal (type II) curves, while at 10 °C, they were of type V and Type I at 25 °C for both adsorption and desorption processes. Five sorption models were tested to fit the experimental data. Halsey's model for 10 °C, Caurie's model for 25 °C and Modified Mizrahi's model for 37 °C were found to be the best fit. There was a clear hysteresis effect at 10 °C, whereas the effect gradually decreased and diminished at 37 °C.     

A hybrid model of component sharing and platform modularity for optimal product family design

Today's industry faces new challenges such as diverse customer demands, shorter product development cycles and cost pressure, which compel manufacturing firms to change their production paradigm from one-size-fits-all mass production toward mass customisation. Over the past decades, modular design has received great attention as a key enabler for mass customisation, and component sharing and platform modularity have been quite popular strategies for modular design. While modular design approaches and their strategies offer a number of advantages such as late product differentiation and changeability, there are unfortunately negative aspects, for example, sales loss due to reduced performance compared to integral design approaches, which have received little attention. Therefore, we propose a hybrid model of the two strategies in order to develop the most profitable product family. A detailed numerical analysis provides empirical support for the feasibility and effectiveness of the hybrid model.