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Surface wettability has a crucial impact on drop splashing, emulsion dynamics, slip flow for drag reduction, fluid–fluid displacement, and various microfluidic applications. Targeting enhanced oil recovery (EOR) applications, we experimentally investigate the effect of matrix wettability on the invasion morphology and sweep efficiency of viscous oil displaced by different aqueous floods using microfluidics, whose porous network mimics a sandstone structure. For comparison, systematic experiments of the same oil–flood pair are done in both hydrophilic and hydrophobic microfluidic chips. The results show that the hydrophilic microfluidic rock has a remarkable increase in oil recovery by a factor of ≈1.44, compared to the hydrophobic case. In addition, we observe a more pronounced lateral growth of the displacing pattern of aqueous flood for the hydrophilic surface. Finally, we quantitatively explain the increasing factor in the recovery rate and finger width for the hydrophilic vs. hydrophobic rock-liked porous networks by incorporating the contact angle into a scaling analysis. [ABSTRACT FROM AUTHOR]

Intramolecular charge transfer (ICT) is an important factor in the nonlinear optical (NLO) properties of organic molecules. In order to study the effect of ICT on two-photon absorption (TPA) and excited-state absorption (ESA), three chalcone derivatives (1, 2 and 3) with different electron push–pull systems were designed and synthesized. The ICT performance of these chalcone derivatives depends on the electron push–pull systems and mainly includes ultrafast ICT in the femtosecond time domain and long-lived charge transfer state (CTS) in the picosecond time domain, which dominate the performance of molecular TPA and ESA respectively. Hole–electron analysis and femtosecond Z-scan experiment indicate that the TPA cross section of these chalcone derivatives can be effectively enhanced by introducing stronger ultra-fast ICT in the case of little difference in ground-state absorption and expanding the molecular π-conjugated structure. Transient absorption spectrum (TAS) experiments of these compounds in solvents of varying polarities were conducted to visualize the establishment of CTS. The local excited state (LES) and charge transfer state (CTS)-based ESA of these chalcone derivatives are extremely dependent on the strength of ICT. Our experimental results show that the superposition of LES and CTS by enhancing ICT performance can effectively improve the ESA, which offers us a practical method to improve the long-impulse response of organic materials. [ABSTRACT FROM AUTHOR]

Carbon capture and sequestration (CCS) in a deep saline aquifer is one of the most promising technologies to mitigate anthropologically emitted carbon dioxide. Accurately quantifying the mass transport of CO2 at pore-scales is crucial but challenging for successful CCS deployment. Here, we conduct high-pressure microfluidic experiments, mimicking reservoir conditions up to 9.5 MPa and 35 °C, to elucidate the microfluidic mass transfer process of CO2 at three different states (i.e., gas, liquid, and supercritical phase) into water. We measure the size change of CO2 micro-bubbles/droplets generated using a microfluidic T-junction to estimate the volumetric mass transfer coefficient (kLa), quantifying the rate change of CO2 concentration under the driving force of concentration gradient. The results show that bubbles/droplets under high-pressure conditions reach a steady state faster than low pressure. The measured volumetric mass transfer coefficient increases with the Reynolds number (based on the liquid slug) and is nearly independent of the injection pressure for both the gas and liquid phases. In addition, kLa significantly enlarges with increasing high pressure at the supercritical state. Compared with various chemical engineering applications using millimeter-sized capillaries (with typical kLa measured ranging from ≈0.005 to 0.8 s−1), the microfluidic results show a significant increase in the volumetric mass transfer of CO2 into water by two to three orders of magnitude, O (102–103), with decreasing hydrodynamic diameter (of ≈50 μm). [ABSTRACT FROM AUTHOR]

[Fe2(TPA)2(μ-O)Cl2]2+ (TPA = tris(2-pyridylmethyl)amine) was investigated as a pre-catalyst, and greatly enhanced the photocatalytic water oxidation activity of BiVO4. An extremely high oxygen yield of 99.1% and apparent quantum yield of 44.3% were obtained in the BiVO4–NaIO3 photocatalytic water oxidation system. [ABSTRACT FROM AUTHOR]

The use of salts as grinding media to assist the mechanosynthesis, and the following one-pot mechanochemical post-synthesis, of hierarchically porous MOFs was carried out efficiently by ball milling. NaCl or KCl were used as a solid solvent to initially pre-grind with 1,3,5-benzenetricarboxylic acid (H3BTC) and copper acetate monhydrate, respectively, for 1 minute, then both mixtures were combined together for a further 20 minutes of grinding, and the resultant mixture was finally washed with ethanol and water to obtain the hierarchically micro-, meso- and macroporous HKUST-1 with a high yield. Moreover, the post-synthesis of these as-obtained hierarchically porous HKUST-1 was easily performed via grinding triethylenediamine (TED) with the above unwashed crude-products for 20 minutes. By adjusting the amount of NaCl and TED added, we simply fabricated the pore- and function-adjustable hierarchically porous HKUST-1. Furthermore, these as-obtained HKUST-1 products showed high performance in the capture of volatile iodine. [ABSTRACT FROM AUTHOR]

Pyrene is considered as one of the most promising nonlinear functional building blocks. The nonlinear optical properties of materials can be improved by modifying the main nonlinear group possession ratio occupied in frontier molecular orbitals. Accordingly, we designed and synthesized two isomeric molecules based on pyrene for ultrafast broadband optical limiters. Different pyrene possession ratios occupied in frontier molecular orbitals were calculated through quantum chemical methods between two molecules. The higher average pyrene possession ratio occupied in frontier molecular orbitals exhibited better nonlinear properties in such structures, which was consistent with the experimental data. Excellent optical limiting behaviors were observed under femtosecond laser excitations at multiple wavelengths (range from 515 to 900 nm), which resulted from two-photon absorption (TPA) and TPA induced excited-state absorption (ESA). Moreover, the sample exhibited extremely high transmittance (＞91%) from visible to infrared regions (500 to 900 nm). Our results show that pyrene-based derivatives can be considered as promising candidates for broadband ultrafast optical limiters. [ABSTRACT FROM AUTHOR]

Ternary mixtures composed of polyisobutylene (PIB), polyethylene oxide (PEO), and silica particles yield three distinct open-pore morphologies depending on the mixture composition: (1) pendular network (particles bonded together by menisci of PEO); (2) capillary aggregate network (particles and PEO form a combined phase with strongly solid-like properties which forms a percolating network); (3) cocontinuous morphology (silica and the PEO form a highly viscous combined phase which retards interfacial tension-driven coarsening). Remarkably, interfacial tension plays altogether different roles in stabilizing these three morphologies: stabilizing the first, not affecting the second, and destabilizing the last. The first two of these morphologies appear to be generalizable to other systems, e.g. to oil/water/particle mixtures. In all three cases, the pores do not collapse even after flow, i.e. all three porous morphologies are amenable to processing. [ABSTRACT FROM AUTHOR]

Fabrication of anti-wetting coatings with anti-biofouling and anti-biofilm properties has become a hot spot of attention in recent years. However, the anti-biofilm mechanism of anti-bacterial adhesion coatings with different wet resistance properties has not been explored in detail. In this work, SiO x micro-nano particles were prepared by the Stöber method and were in situ modified. The SiO x /waterborne polyurethane (WPU) coatings were prepared by the drop coating method, and the coatings with different hydrophobic and oleophobic properties were constructed by modifying the process conditions using SiO x micro-nano particles as the roughness construction factor. Taking the dominant spoilage bacteria of aquatic products, Shewanella putrefaciens as the object, the anti-bacterial adhesion properties and anti-biofilm mechanism of the SiO x /WPU coatings were investigated. The results show that, with the unmodified SiO x particles increasing from 1.2% (w/V) to 4.0% (w/V), the hydrophobicity and thermal stability of the SiO x /WPU coatings are significantly enhanced, but the oil repellency becomes worse due to the mesoporous structure. After SiO x micro-nano particles are modified with 1 H ,1 H ,2 H ,2 H -perfluorooctyl trichlorosilane (PFOTS), the surface energy of the SiO x /WPU coatings is decreased, the liquid repellency is improved, and the surfaces are rough with the appearance of fluorocarbon compounds, but the thermal stabilities are slightly reduced. Among them, after the secondary modification of SiO x micro-nano particles, the SiO x /WPU coatings showed excellent oil repellency, lower surface energies and higher fluorocarbon content on the surface. Particularly, SiO x /WPU coatings exhibited super-amphiphobicity after adjusting the amount of concentrated ammonia added during the secondary modification process. Meanwhile, we found that for the hydrophobic SiO x /WPU coatings, the stronger the oleophobic property, the greater the anti-bacterial adhesion ability is, while the anti-bacterial adhesion ability of hydrophobic and selectively oleophobic or superhydrophobic and oleophobic SiO x /WPU coatings is poor than that of amphiphilic SiO x /WPU coatings. However, because the super-amphiphobic SiO x /WPU coatings can be in the Cassie state with the bacterial solution for a long time, it can "capture" enough air to inhibit the irreversible adhesion of the bacteria. More importantly, the coatings can also inhibit the metabolic activity, secretion of extracellular polysaccharides, and activities of ATPase and AKP of the adherent bacteria, so it has a better anti-biofilm property. The anti-biofilm coatings can be used as food packaging materials or coated on the inner surface of packaging boxes to prevent the microbial infection.

Carbon capture and sequestration (CCS) in a deep saline aquifer is one of the most promising technologies to mitigate anthropologically emitted carbon dioxide. Accurately quantifying the mass transport of CO 2 at pore-scales is crucial but challenging for successful CCS deployment. Here, we conduct high-pressure microfluidic experiments, mimicking reservoir conditions up to 9.5 MPa and 35 °C, to elucidate the microfluidic mass transfer process of CO 2 at three different states ( i.e. , gas, liquid, and supercritical phase) into water. We measure the size change of CO 2 micro-bubbles/droplets generated using a microfluidic T-junction to estimate the volumetric mass transfer coefficient ( k L a ), quantifying the rate change of CO 2 concentration under the driving force of concentration gradient. The results show that bubbles/droplets under high-pressure conditions reach a steady state faster than low pressure. The measured volumetric mass transfer coefficient increases with the Reynolds number (based on the liquid slug) and is nearly independent of the injection pressure for both the gas and liquid phases. In addition, k L a significantly enlarges with increasing high pressure at the supercritical state. Compared with various chemical engineering applications using millimeter-sized capillaries (with typical k L a measured ranging from ≈0.005 to 0.8 s -1 ), the microfluidic results show a significant increase in the volumetric mass transfer of CO 2 into water by two to three orders of magnitude, O (10 2 -10 3 ), with decreasing hydrodynamic diameter (of ≈50 μm).

[Fe2(TPA)2(μ-O)Cl2]2+ (TPA = tris(2-pyridylmethyl)amine) was investigated as a pre-catalyst, and greatly enhanced the photocatalytic water oxidation activity of BiVO4. An extremely high oxygen yield of 99.1% and apparent quantum yield of 44.3% were obtained in the BiVO4-NaIO3 photocatalytic water oxidation system.

The use of salts as grinding media to assist the mechanosynthesis, and the following one-pot mechanochemical post-synthesis, of hierarchically porous MOFs was carried out efficiently by ball milling. NaCl or KCl were used as a solid solvent to initially pre-grind with 1,3,5-benzenetricarboxylic acid (H3BTC) and copper acetate monhydrate, respectively, for 1 minute, then both mixtures were combined together for a further 20 minutes of grinding, and the resultant mixture was finally washed with ethanol and water to obtain the hierarchically micro-, meso- and macroporous HKUST-1 with a high yield. Moreover, the post-synthesis of these as-obtained hierarchically porous HKUST-1 was easily performed via grinding triethylenediamine (TED) with the above unwashed crude-products for 20 minutes. By adjusting the amount of NaCl and TED added, we simply fabricated the pore- and function-adjustable hierarchically porous HKUST-1. Furthermore, these as-obtained HKUST-1 products showed high performance in the capture of volatile iodine.