RSC Advances

Cha, Wang Soo; Talapaneni, Siddulu Naidu; Kempaiah, Devaraju M.; Joseph, Stalin; Lakhi, Kripal Singh; Al-Enizi, Abdullah M.; Park, Dae-Hwan; Vinu, Ajayan

doi: 10.1039/c8ra01281dpmid: 35539254

Highly ordered and three-dimensional (3-D) mesoporous carbon materials were prepared through a nano-hard templating approach using FDU-12 silica with tunable pore sizes as a template, which was synthesized via a microwave-assisted method. Powder XRD and microscopic techniques such as HR-TEM, HR-SEM, and N2 adsorption–desorption techniques were employed to characterize the structure and textural properties of the prepared mesoporous carbon samples. The characterization results reveal that all the mesoporous carbon samples show a 3-D porous mesostructure with tunable pore diameters (5.7 to 9.4 nm) and a large specific surface area in the range from 451 to 1251 m2 g−1. The supercapacitive behavior of the cubic structured mesoporous carbons was determined using cyclic voltammetry, electrochemical impedance and charge–discharge measurements. The cubic mesoporous carbon materials exhibit a superior capacitive performance with a high specific capacitance value of 315.3 F g−1 at the current density of 1 A g−1, which is much higher than that of hexagonally-ordered mesoporous carbon with large pore diameters, activated carbon, and carbon nanotubes. The materials also show excellent cyclic stability and extremely low resistance. The superior specific capacitance of these materials is attributed to the combination of excellent surface properties such as large specific surface area, large pore volume and uniform pore diameter, spherical morphology, and a 3-D porous system with cage-type pores.

Moon, Ji Su; Ahn, Dae Hyun; Kim, Si Woo; Lee, Seung Yeon; Lee, Ju Young; Kwon, Jang Hyuk

doi: 10.1039/c8ra01761apmid: 35539237

Two bipolar host materials, 8-(9H-carbazol-9-yl)-5-(pyridin-2-yl)-5H-pyrido[3,2-b]indole (CzCbPy) and 5-(6-(9H-carbazol-9-yl)pyridin-2-yl)-8-(9H-carbazol-9-yl)-5H-pyrido[3,2-b]indole (2CzCbPy), were synthesized for deep blue thermally activated delayed fluorescence organic light emitting diodes (TADF OLEDs). Both CzCbPy and 2CzCbPy hosts possess bipolar characteristic with high polarity, which results in high delayed photoluminescence quantum yields by reducing the energy gap between singlet and triplet states of TADF materials. In addition, these hosts have high enough triplet energies of 3.05 eV to transfer exciton energy to a deep blue TADF emitter. A deep blue TADF OLED fabricated with a CzCbPy host exhibited high external quantum efficiency of 22.9% and low efficiency roll-off (19.2% at 1000 cd m−2).

Qin, Xinmao; Yan, Wanjun; Guo, Xiaotian; Gao, Tinghong

doi: 10.1039/c8ra02415dpmid: 35539233

Molecular dynamics simulations with adaptive intermolecular reactive empirical bond order (AIREBO) potential are performed to investigate the effects of rectangular nanoholes with different areas, aspect ratios (length/width ratios) and orientations on the tensile strength of defective graphene. The simulations reveal that variation of area, aspect ratio and orientation of rectangular nanohole can significantly affect the tensile strength of defective graphene. For example, defective graphene with a larger area of rectangular nanohole shows a bigger drop in tensile strength. It was found that the tensile strength of both armchair and zigzag edged graphene monotonically decreases with area increases in rectangular nanohole. Changes in aspect ratio and orientation of rectangular nanohole, however, can either decrease or increase the tensile strength of defective graphene, dependent on the tensile direction. This study also presents information that the tensile strength of defective graphene with large area of nanohole is more sensitive to changes in aspect ratio and orientation than is defective graphene with small area of nanohole. Interestingly, variation of tensile strength of defective graphene from MD simulations is in good agreement with predictions from energy-based quantized fracture mechanics (QFM). The present results suggest that the effect of nanoholes on the tensile strength of graphene provides essential information for predictive optimization of mechanical properties and controllable structural modification of graphene through defect engineering.

Ghosh, Tuhin; Karak, Niranjan

doi: 10.1039/c8ra01766bpmid: 35539268

Smart biodegradable tough interpenetrating polymer networks (IPNs) of bio-based polyurethane containing a silicone moiety and polystyrene at three different compositions were synthesized for the first time by using simultaneous polymerization technique. The structures of the synthesized IPNs were interpreted by FTIR, NMR, and XRD analyses, while morphology was provided from a SEM study. The synthesized IPNs exhibited outstanding elongation at break (up to 1608%) along with good tensile strength (up to 12.6 MPa), toughness (up to 92.34 MJ m−3), impact resistance (up to 26.8 kJ m−1), scratch resistance (up to 6.5 kg) and durometer hardness (up to 86 Shore A). Furthermore, the synthesized IPNs exhibited good thermal stability up to 245 °C and chemical resistance. Interestingly, these IPNs showed multi-stimuli responsive self-healing (within 62 s at 450 W microwave and 6–8 min under sunlight) and shape memory (100% shape recovery within 48 s with a 450 W microwave and 7–13 min under direct sunlight) behavior. A self-cleaning attribute was also observed for the synthesized IPNs which showed a static contact angle up to 120.8° and angle of hysteresis <5°. Most interestingly, the synthesized IPNs also exhibited moderate bio-degradation under the exposure to a P. aeruginosa bacterial strain. Therefore, the synthesized smart bio-degradable tough IPNs with the above properties have great potential for different advanced multifaceted applications.

Huang, Xue; Diao, Guiqiang; Li, Siqi; Balogun, Muhammad-Sadeeq; Li, Nan; Huang, Yongchao; Liu, Zhao-Qing; Tong, Yexiang

doi: 10.1039/c8ra02529kpmid: 35539253

Herein, flexible carbon fiber cloth (CFC) is modified by embedding Ni nanoparticles via a thermal reduction strategy, and it is used as a suitable anode material for lithium-ion batteries. Benefitting from the elemental interaction between Ni and carbon, the Ni-embedded CFC displayed higher lithium storage properties than pristine CFC and Ni-free porous CFC.

Wang, Genbei; Liu, Yuanxue; Wang, Yu; Gao, Wenyuan

doi: 10.1039/c8ra00797gpmid: 35539228

Rhizoma Paridis saponins (RPS) as active parts of P. polyphylla Smith var. yunnanensis has been used as an anti-cancer drug in traditional Chinese medicine. In this study, RPS was first found to demonstrate a potent effect on markedly reducing the pain induced by cancer. Therefore, the aim of this study was to further explore the analgesic effect of RPS and its possible reaction pathway on H22 hepatocarcinoma cells inoculated in the hind right paw of mice. Cancer-induced pain model mice were randomly divided into 5 groups (n = 10) and orally administered with RPS (50–200 mg kg−1) for 2 weeks. On the last day of treatment, the pain behavior of mice was measured using hot-plate test and open field test, and brain tissues were sampled for detection of biochemical indices, malondialdehyde (MDA), superoxide dismutase (SOD), prostaglandin E2 (PGE2), serotonin (5-HT) and β-endorphin (β-EP). Moreover, the concentrations of NF-κB and IL-1β in the blood serum were measured by ELISA reagent kits. In addition, naloxone, the non-selective antagonist of opioid receptors, was used to identify the opioid receptors involved in RPS's action. It has been found that RPS alleviates cancer pain mainly via the suppression of inflammatory pain induced by oxidative damage, such as decreasing MDA and PGE2 levels, renewing activity of SOD, as well as increasing 5-HT and β-EP in the brain and suppressing the expression of NF-κB and IL-1β in the serum in a concentration-dependent manner. Overall, the current study highlights that RPS has widespread potential antinociceptive effects on a mouse model of chronic cancer pain, which may be associated with the peripheral nervous system and the central nervous system.

Sun, Zhiyuan; Zhou, Shaona; Qiu, Haixia; Gu, Ying; Zhao, Yuxia

doi: 10.1039/c8ra02557fpmid: 35539218

A series of novel water-soluble photosensitizers (PSs; M1–M5) based on 3-cinnamoylcoumarin derivatives, incorporating carboxylic acid salt (M1, M2), pyridine salt (M3, M4) and quaternary ammonium salt (M5) groups, were designed and synthesized. Their photophysical and photochemical properties and in vitro antimicrobial photodynamic inactivation (PDI) were investigated. M2, modified with two carboxylic acid salts, was unstable in phosphate-buffered saline (PBS). The four other PSs all showed higher binding/uptake to methicillin-resistant Staphylococcus aureus (MRSA), A. baumannii and C. albicans compared with the clinical drug methylene blue (MB), except for M1 to A. baumannii. Furthermore, the three cationic PSs (M3–M5) exhibited equivalent antibacterial PDI efficacies against MRSA and A. baumannii compared with MB. The antifungal efficacies of M4 and M5 to C. albicans were both significantly higher than that of MB, especially for M5, indicating that the quaternary ammonium-salt-modified coumarin derivative has substantial potential for antifungal PDI.

Zhang, Haihan; Zhao, Zhenfang; Chen, Shengnan; Wang, Yue; Feng, Ji; Jia, Jingyu; Kang, Pengliang; Li, Sulin

doi: 10.1039/c8ra01295dpmid: 35539271

The geographical variation of denitrifying bacterial communities and water quality parameters in urban lakes distributed across nine provinces in China were determined. The Illumina sequencing data of the denitrifying encoding gene nirS was examined in the samples collected from nine localities (pairwise geographical distance: 200–2600 km). The results showed that fundamental differences in water quality were observed among different urban lakes. The highest nitrate (2.02 mg L−1) and total nitrogen (3.82 mg L−1) concentrations were observed in Pingzhuang (P < 0.01). The algal cell concentration ranged from 1.29 × 108 to 3.0 × 109 cell per L. The sequencing data generated a total of 421058 high quality nirS gene reads that resulted in 6369 OTUs (97% cutoff), with Proteobacteria and Firmicutes being the dominant taxa. A co-occurrence network analysis indicated that the top five genera identified as keystone taxa were Dechlorospirillum sp., Alicycliphilus sp., Dechloromonas sp., Pseudogulbenkiania sp., and Paracoccus sp. A redundancy analysis (RDA) further revealed that distinct denitrifying bacterial communities inhabited the different urban lakes, and influenced by urban lake water ammonia nitrogen, manganese and algal cell concentrations. A variance partitioning analysis (VPA) also showed that geographic location was more important than water quality factors in structuring the denitrifying bacterial communities. Together, these results provide new insight into understanding of denitrifying bacterial communities associated with geographically distributed urban lakes on a larger scale, and these results also expand our exploration of aquatic microbial ecology in freshwater bodies.

Um, Jun Geun; Jun, Yun-Seok; Alhumade, Hesham; Krithivasan, Hariharan; Lui, Gregory; Yu, Aiping

doi: 10.1039/c8ra02087fpmid: 35539231

In this article, polyurethane/graphene nano-platelet (PU/GnP) composites were fabricated via planetary centrifugal mixer (PCM) and cast on polyethylene terephthalate (PET) and copper substrates. Four different grades of GnP are used to investigate the effect of GnP size on the anti-corrosion performance of the composites. Tafel, Nyquist, and Bode plots are used to quantify and compare the anti-corrosion performance of the composites, and these plots are obtained by electrochemical analysis. In addition to the anti-corrosion performance, mechanical properties and morphologies of the composites are analyzed. Various parameters indicating the anti-corrosion performance illustrate that smaller size of GnP in the composites shows higher anti-corrosion performance on copper substrate. The results show that the smaller size of GnP is not only uniformly dispersed within PU, but also offers a high surface area which helps construct an efficient filler pathway that suppresses the diffusion of a corrosive agent into the polymer matrix. Nevertheless, mechanical properties of the composites are partially improved. Essentially, this study demonstrates that the size of GnP plays a central role in determining the anti-corrosion performance of PU/GnP composites.

Norton, Angela M.; Nguyen, Hannah; Xiao, Nicholas L.; Vlachos, Dionisios G.

doi: 10.1039/c8ra03088jpmid: 35539252

While homogeneous metal halides have been shown to catalyze glucose to fructose isomerization, direct experimental evidence in support of the catalytically active species remains elusive. Here, we integrate direct speciation methods with kinetics to provide strong evidence for the active species of AlCl3 in glucose–fructose isomerization in water. We investigate the effect of Lewis (AlCl3) and Brønsted (HCl) acids on aluminum hydrolysis and glucose conversion. We demonstrate the interplay between the acids using the Optimum Logic Inc. speciation model (OLI software). We measure aqueous aluminum species and protons through in situ and ex situ 27Al quantitative nuclear magnetic resonance (qNMR) and pH measurements, respectively, and quantify aluminum nanoparticles through a combination of inductively coupled plasma-mass spectrometry (ICP-MS), dynamic light scattering (DLS), and ultrafiltration. Direct speciation measurements correlated with the glucose isomerization rate indicate that the hydrolyzed Al(iii) complex [Al(H2O)4(OH)2]1+ is the active species in glucose isomerization.