Evaluation of kinetic parameters for the crystallization and degradation process of synthesized strontium mercaptosuccinate functionalized poly(ε-caprolactone) by non-isothermal approach

Strontium (Sr) mercaptosuccinate (MS) functionalized poly(ε-caprolactone) (PCL) was prepared by ring opening polymerization technique in the presence of Sr-MS nanohybrid initiator and stannous octoate (SO) catalyst for 2 h at 160 °C under nitrogen atmosphere. FTIR, NMR, DSC, TGA, GPC, POM, TEM and AFM techniques were employed to characterize the Sr-MS functionalized polymer. The FTIR spectrum showed a small peak at 526 cm⁻¹ due to the Sr–O stretching. The particle size of the Sr-MS nanohybrid functionalized PCL matrix was determined as less than 30 nm. The crystallization rate and crystallinity percentage were estimated from the non-isothermal exothermic curves. The crystallization temperature (T_c) was found to be decreased with increasing the cooling rate whereas the degradation temperature (T_d) was increased with increasing the heating rate. Various kinetic models were applied to comprehend the degradation behaviour of Sr-MS functionalized PCL as well as its related kinetic parameters under non-isothermal condition. The activation energy (E_a) was calculated for both crystallization (138.5 kJ/mol) and degradation (187 kJ/mol) behaviours of Sr-MS functionalized PCL under non-isothermal condition.

     

A Stretchable and Self‐Healing Energy Storage Device Based on Mechanically and Electrically Restorative Liquid‐Metal Particles and Carboxylated Polyurethane Composites

Stretchable and self‐healing (SH) energy storage devices are indispensable elements in energy‐autonomous electronic skin. However, the current collectors are not self‐healable nor intrinsically stretchable, they mostly rely on strain‐accommodating structures that require complex processing, are often limited in stretchability, and suffer from low device packing density and fragility. Here, an SH conductor comprising nickel flakes, eutectic gallium indium particles (EGaInPs), and carboxylated polyurethane (CPU) is presented. An energy storage device is constructed by the two SH electrodes assembled with graphene nanoplatelets sandwiching an ionic‐liquid electrolyte. An excellent electrochemical healability (94% capacity retention upon restretching at 100% after healing from bifurcation) is unveiled, stemming from the complexation modulated redox behavior of EGaIn in the presence of the ligand bis(trifluoromethanesulfonyl)imide, which enhances the reversible Faradaic reaction of Ga. Self‐healing can be achieved where the damaged regions are electrically restored by the flow of liquid metal and mechanically healing activated by the interfacial hydrogen bonding of CPU with an efficiency of 97.5% can be achieved. The SH conductor has an initial conductivity of 2479 S cm^?1 that attains a high stretchability with 700% strain, it restores 100% stretchability even after breaking/healing with the electrical healing efficiency of 75%.     

Optimizing deep belief network parameters using grasshopper algorithm for liver disease classification

Image processing plays a vital role in many areas such as healthcare, military, scientific and business due to its wide variety of advantages and applications. Detection of computed tomography (CT) liver disease is one of the difficult tasks in the medical field. Hand crafted features and classifications are the two types of methods used in the previous approaches, to classify liver disease. But these classification results are not optimal. In this article, we propose a novel method utilizing deep belief network (DBN) with grasshopper optimization algorithm (GOA) for liver disease classification. Initially, the image quality is enhanced by preprocessing techniques and then features like texture, color and shape are extracted. The extracted features are reduced by utilizing the dimensionality reduction method like principal component analysis (PCA). Here, the DBN parameters are optimized using GOA for recognizing liver disease. The experiments are performed on the real time and open source CT image datasets which embraces normal, cyst, hepatoma, and cavernous hemangiomas, fatty liver, metastasis, cirrhosis, and tumor samples. The proposed method yields 98% accuracy, 95.82% sensitivity, 97.52% specificity, 98.53% precision, and 96.8% F-1 score in simulation process when compared with other existing techniques.     

Water-Processable,Stretchable, Self-Healable,Thermally Stable,and Transparent Ionic Conductors for Actuators and Sensors

For emerging biocompatible, wearable, and stretchable epidermal electronic devices, it is essential to realize novel stretchable conductors with the attributes of transparency, low-cost and nontoxic components, green-solvent processbility, self-healing, and thermal stabililty. Although conducting materials–rubber composites, ionic hydrogels, organogels have been developed, no stretchable material system that meets all the outlined requirements has been reported. Here, a series of P(SPMA-r-MMA) polymers with different ratios of ionic side chains is designed and synthesized, and it is demonstrated that the resulting stretchable ionic conductors with glycerol are transparent, water processable, self-healable, and thermally stable due to the chemically linked ionic side chain, satisfying all of the aforementioned requirements. Among the series of polymer gels, the P(SPMA_0.75-r-MMA_0.25) gel shows optimum conductivity (6.7 × 10⁻⁴ S cm⁻¹), stretchability (2636% of break at elongation), and self-healing (98.3% in 3 h) properties. Accordingly, the transparent and self-healable P(SPMA_0.75-r-MMA_0.25) gels are used to realize thermally robust actuators up to 100 °C and deformable and self-healable thermal sensors.     

Microfluidic-based biosensor: signal enhancement by gold nanoparticle

Biosensor is an analytical device to detect the biomolecules assisted by the transducer and physicochemical detector. A good biosensor is expecting to be with low cost, easy to perform and identify the results without prior experience. In addition, a good biosensor has two main key characteristics such as sensitivity and specificity; these are mainly determined by the affinity of biomolecules with the assistance of sensing system. Microfluidic-based lab-on-chip is one of the fast growing technologies in the field of biosensor bring the positive characteristics with a fast delivery set-up. On the other hand, gold nanoparticle (GNP) is the powerful tool to enhance the biomolecular detection with higher sensitivity and it has been proved for the effective applications with different sensors. In this review, we discussed the applications of microfluidic-based delivery and GNP for biosensing with the new level of developments, which elevate a step ahead.     

Optically poled SHG and THG effects in cesium doped zinc oxide nanorods

The hexagonal wurtzite structure of the synthesized undoped and cesium (Cs) doped zinc oxide (ZnO) nanorods were confirmed with X-ray diffraction patterns. Further analysis with field emission scanning electron microscope images and energy dispersive X-ray spectra revealed the c-axis oriented hexagonal morphology of the samples with chemical composition. Optical poling through 337 nm nitrogen laser has been adopted to enhance the nonlinear optical properties. When the power density of the fundamental laser beam from Nd:YAG laser of 1064 nm matched with the band edge of the samples, resonant absorption takes place leading to the enhanced NLO properties. The interstitial occupancy of the dopants in 3 and 5 mol% CsZnO increases the band tailing in the forbidden energy gap. The minimum of Urbach energy calculated from UV–Vis absorption spectra corresponding to 1 mol% CsZnO revealed more ordering in the sample. More enhanced second and third order NLO effects were observed in this sample having larger crystallite size, lesser diameter, lesser band gap, minimum urbach energy and higher electron–phonon interaction.     

A Series of Hybrid Multifunctional Interfaces as Artificial SEI Layer for Realizing Dendrite Free,and Long-Life Sodium Metal Anodes (Adv. Funct. Mater. 42/2023)

Sodium metal (Na) anodes are considered the most promising anode for high-energy-density sodium batteries because of their high capacity and low electrochemical potential. However, Na metal anode undergoes uncontrolled Na dendrite growth, and unstable solid electrolyte interphase layer (SEI) formation during cycling, leading to poor coulombic efficiency, and shorter lifespan. Herein, a series of Na-ion conductive alloy-type protective interface (Na-In, Na-Bi, Na-Zn, Na-Sn) is studied as an artificial SEI layer to address the issues. The hybrid Na-ion conducting SEI components over the Na-alloy can facilitate uniform Na deposition by regulating Na-ion flux with low overpotential. Furthermore, density functional study reveals that the lower surface energy of protective alloys relative to bare Na is the key factor for facilitating facile ion diffusion across the interface. Na metal with interface layer facilitates a highly reversible Na plating/stripping for ≈790 h, higher than pristine Na metal (100 h). The hybrid self-regulating protective layers exhibit a high mechanical flexibility to promote dendrite free Na plating even at high current density (5 mA cm⁻²), high capacity (10 mAh cm⁻²), and good performance with Na₃V₂(PO₄)₃ cathode. The current study opens a new insight for designing dendrite Na metal anode for next generation energy storage devices.     

Synthesis and Polymerization of Bismaleimide Derived from 5(6)-amino-1(4′-aminophenyl)-1,3,3′-trimethyl indane

The acid-catalyzed dimerization of α-methyl styrene led to the formation of trimethyl phenyl indane, which on nitration followed by reduction using hydrazine hydrate gave 5(6)-amino-1(4′-aminophenyl)-1,3,3′-trimethyl indane. This aromatic diamine was used to synthesize bismaleamic acid and imidized to yield bismaleimide. The bismaleamic acid was converted to prepolymer directly by imidizing it in refluxing toluene. All the materials synthesized were characterized using FTIR, ¹H and ¹³C NMR. The direct inlet mass spectral characterizations were carried out for bismaleamic acid, bismaleimide and bismaleimide prepolymer. The fragmentation pattern was discussed in detail and the structure proposed was confirmed. The thermogravimetric studies were done for all the materials and kinetic parameters (energy of activation and frequency factor) were calculated using Dharwadkar and Kharkhanavala method. The structural changes occurring in the thermally polymerized bismaleimide and bismaleimide prepolymer were discussed.