Anionic Sulfonate Research Articles

Utilization of Pt Nanoparticle Catalysts during Capillary Condensation Phenomenon in PEMFC: A Lattice DFT Simulation Based on 3D Reconstruction of TEM Images

The use of porous carbon support particles in Cathode Catalyst Layer (CCL) of Polymer Electrolyte Membrane Fuel Cell (PEMFC) has gained significant interest due to their ability to enable proper dispersion of Platinum (Pt) nanoparticles [1]. This offers a key advantage of avoiding the Pt nanoparticles from potential poisoning by sulfonate anion functional groups in the ionomer that is deposited on the surface of the support particles [2]. Furthermore, the presence of condensed liquid water is essential for effective utilization of the Pt nanoparticles that are dispersed both inside and outside of the porous carbon support particles. This is because water plays a crucial role as a proton pathway for hydrogen ions during the electrochemical reaction, thus a requisite amount of condensed liquid water is also needed to promote efficient catalytic activity and maximize the performance of Pt nanoparticle catalysts. It has been demonstrated that the microstructure characteristics of the porous carbon support particles have a significant impact on the performance of Pt utilization, which is attributed to the varying behavior of water condensation [2]. Microstructure properties such as pore size, surface area, and wettability properties, can influence the distribution of condensed liquid water, thereby affecting the electrochemical performance of Pt nanoparticles in the catalyst layer of PEMFC. Understanding the effect of capillary water condensation in the porous carbon support particles is therefore crucial for maximizing the utilization and catalytic activity of Pt nanoparticles in fuel cell systems.To investigate the behavior of water condensation in the CCL particles of PEMFC, we conducted simulations based on reconstructed structural data obtained from Transmission Electron Microscopy (TEM) images, as shown in Figure 1. The CCL particle used in this study is taken from the Toyota MIRAI Gen 2 model, an emerging commercial PEMFC-based vehicle in Japan. Here, we used the lattice Density Functional Theory (DFT) to simulate the process of capillary water condensation within the pore network of the particle. The lattice DFT method, which is based on the mean-field lattice gas model, can be interpreted as a coarse-grained equivalent of the conventional DFT [3]. The significant advantage of using lattice DFT is to provide a simple model and computationally efficient approach for studying the behavior of capillary water condensation. To validate the parameters used in our lattice DFT simulations, we compared the isotherm curve obtained from our simulation results with experimental data. Through this comparison, we were able to fine-tune the parameters of the lattice DFT simulation to fit the simulated isotherm curve with that of the experiment. When the parameters are optimized, the resulting water distribution obtained from the lattice DFT simulation, as illustrated in Figure 1, serves as a crucial input to investigate the utilization/activation of Pt nanoparticles within and outside the carbon support particle under varying relative humidity (RH) conditions. Since the resulting water distribution depends on RH, we expect that the utilization/activation of Pt nanoparticles also depend on RH. In this study, we defined utilization/activation of Pt nanoparticle when there is a continuous path of condensed water connecting the Pt nanoparticle to the surface of the carbon support particle. This criterion is similar to the case when we assume that the ionomer is distributed uniformly on the surface of the carbon support particle. Our investigation shows that the utilization/activation behavior of Pt nanoparticles follows closely the isotherm curve of the capillary water condensation.The complex internal structure of CCL particles in PEMFC makes it challenging to visualize and understand their workings through experiments alone. Therefore, our approach of using lattice DFT simulations offers valuable insights to the role of capillary water condensation behavior in the utilization/activation of Pt nanoparticles. This approach may also pave the way for future research in optimization strategies for PEMFC, ultimately contributing to the advancement of clean energy technologies.This work was supported by the New Energy and Industrial Technology Development Organization (NEDO) of Japan (Grant number JPNP20003).[1] Islam, M.N., et al. (2022), Nat. Commun. 13, 6157.[2] Ramaswamy, N., et al. (2020) J. Electrochem. Soc. 167 064515.[3] Monson, P. (2012) Micropor. Mesopor. Mater. 160, 47–66.Figure 1. Reconstructed structural data obtained from TEM images of a PEMFC CCL particle used in Toyota MIRAI Gen 2 model, with visualization of condensed water obtained from a sample lattice DFT simulation. Figure 1

A molecular sieve with ultrafast adsorption kinetics for propylene separation

The design of molecular sieves is vital for gas separation, but it suffers from a long-standing issue of slow adsorption kinetics due to the intrinsic contradiction between molecular sieving and diffusion within restricted nanopores. We report a molecular sieve ZU-609 with local sieving channels that feature molecular sieving gates and rapid diffusion channels. The precise cross-sectional cutoff of molecular sieving gates enables the exclusion of propane from propylene. The coexisting large channels constituted by sulfonic anions and helically arranged metal-organic architectures allow the fast adsorption kinetics of propylene, and the measured propylene diffusion coefficient in ZU-609 is one to two orders of magnitude higher than previous molecular sieves. Propylene with 99.9% purity is obtained through breakthrough experiments with a productivity of 32.2 L kg −1 .

Molecular Engineering of Copper Phthalocyanine for CO2 Electroreduction to Methane.

Efficient electrochemical CO2 reduction reaction (ECO2RR) to multi-electron reductive products remains a great challenge. Herein, molecular engineering of copper phthalocyanines (CuPc) was explored by modifying electron-withdrawing groups (EWGs) (cyano, sulfonate anion) and electron-donating groups (EDGs) (methoxy, amino) to CuPc, then supporting onto carbon paper or carbon cloth by means of droplet coating, loading with carbon nanotubes and coating in polypyrrole (PPy). The results showed that the PPy-coated CuPc effectively catalysed ECO2RR to CH4. Interestingly, experimental results and DFT calculations indicated EWGs markedly improved the selectivity of methane for the reason that the introduction of EWGs reduces electron density of catalytic active center, resulting in a positive move to initial reduction potential. Otherwise, the modification of EDGs significantly reduces the selectivity towards methane. This electronic effect and heterogenization of CuPc are facile and effective molecular engineering, benefitting the preparation of electrocatalysts for further reduction of CO2.

Enhancement in Capacitance of Ionic Type of EAP-Based Strain Sensors

This paper aims to enhance the capacitance of electroactive polymer (EAP)-based strain sensors. The enhancement in capacitance was achieved by using a free-standing stretchable polymer film while introducing conducting polymer to fabricate a hybrid dielectric film with controlled conductivity. In this work, styrene-ethylene-butylene-styrene (SEBS) rubber was used as the base material, and dodecyl benzene sulfonate anion (DBSA)-doped polyaniline (PANI) was used as filler to fabricate a hybrid composite conducting film. The maleic anhydride group of the SEBS Rubber and DBSA, the anion of the polyaniline dopant, make a very stable dispersion in Toluene and form a free-standing stretchable film by solution casting. DBSA-doped polyaniline increased the conductivity and dielectric constant of the dielectric film, resulting in a significant enhancement in the capacitance of the EAP-based strain sensor. The sensor presented in this article exhibits capacitance values ranging from 24.7 to 100 µF for strain levels ranging from 0 to 100%, and sensitivity was measured 3 at 100% strain level.

Molecular dynamics models to investigate the diffusion behavior of emulsified asphalt

The utilization of emulsified asphalt is widespread in the recycling of asphalt pavement due to its eco-friendliness and energy efficiency. While numerous research studies have been conducted on the mixture design and strength assessment of emulsified asphalt, the mechanism by which it diffuses and adheres to the aggregate surface remains inadequately comprehended. This study developed molecular dynamics models to investigate the diffusion behavior of emulsified asphalt on the aggregate surface to clarify the role of emulsifier, water, and asphalt in the adsorption process from a molecular perspective. Interface models are established according to the diffusion state for interfacial adhesion evaluation. The results show that the movement of water molecules is the driving force for the entire emulsified asphalt to adsorb to the aggregate surface, whether the aggregate is silica or reclaimed asphalt pavement (RAP). Compared with anionic surfactant Sodium Dodecylbenzene Sulfonate (SDBS), cationic emulsifier Cetyltrimethylammonium Chloride (CTAC) has a better affinity, stronger adsorption, and higher interfacial adhesion energy with silica. Compared with RAP, emulsified asphalt is more readily adsorbed to the surface of silica. It is concluded that emulsifiers have two distribution conformations during the adsorption process, delamination, and aggregation, with delamination exhibiting stronger interface strength with silica than aggregation. When the emulsified asphalt spreads on the RAP surface, the penetration of water molecules into the aged asphalt layer in the RAP structure reduces the structure's water resistance. These results can provide a molecular perspective for understanding the internal structure of emulsified cold recycle mixture (ECRM) and link the adsorption behavior of emulsified asphalt on aggregate surfaces with the internal interface strength of ECRM.

The Effect of Anion Modification on the Conductive Polymer/Ag‐Interdigitated Electrodes Micro‐Supercapacitor

Due to their outstanding electrical conductivity, simplicity of synthesis, and exceptional flexibility, conductive polymers are the most attractive electrode materials for micro‐supercapacitors (MSCs). However, when used as an electrode material alone, its poor capacitive performance and cycle‐life hinder the wide engineering applications. Herein, a polypyrrole (PPy)/Ag‐interdigitated electrodes MSCs is proposed, and the impact of aromatic sulfonic acid group anion modification on the electrochemical properties and flexibility of PPy/Ag MSCs is investigated. In the results, it is shown that different aromatic sulfonic‐acid‐based anionic dopants have different effects on the properties of PPy films. Among the prepared three PPy/Ag MSCs devices, PPy:anthraquinone‐2‐sulfonic acid/Ag MSCs have the highest areal capacitance (198.8 mF cm−2) at a current density of 0.5 mA cm−2, surpassing PPy:2‐naphthalenesulfonic acid/Ag MSCs (114.3 mF cm−2) and PPy:p‐toluenesulfonic acid monohydrate/Ag MSCs (89.7 mF cm−2). Furthermore, at a power density of 0.25 mW cm−2, the PPy:AQS/Ag MSCs exhibit a high energy density of 27.61 μWh cm−2, which is above the most of the previously reported PPy‐based MSCs. Therefore, in this research, the groundwork is provided for improving properties of flexible MSCs based on PPy.

Formation of Polyion Complex Aggregate Formed from a Cationic Block Copolymer and Anionic Polysaccharide.

Block copolymers (PmMn; P20M101 and P100M98) comprising poly(2-(methacryloyloxy)ethylphosphorylcholine) (PMPC, P) containing biocompatible phosphorylcholin pendants and cationic poly((3-acryloylaminopropyl) trimethylammonium chloride) (PMAPTAC, M) were synthesized via a controlled radical polymerization method. The degrees of polymerization of the PMPC and PMAPTAC segments are denoted by subscripts (PmMn). The mixture of cationic PmMn and anionic sodium chondroitin sulfate C (CS) with the pendant anionic carboxylate and sulfonate groups formed polyion complex (PIC) aggregates in phosphate-buffered saline. A charge-neutralized mixture of P20M101 with CS formed P20M101/CS PIC vesicles with a hydrodynamic radius (Rh) of 97.2 nm, zeta potential of ca. 0 mV, and aggregation number (Nagg) of 23,044. PMPC shells covered the surface of the PIC vesicles. The mixture of P100M98 and CS formed PIC spherical micelles with the PIC core and hydrophilic PMPC shells. The Rh, zeta potential, and Nagg of the PIC micelles were 26.4 nm, ca. 0 mV, and 404, respectively. At pH < 4, the carboxylate anions in CS were protonated. Thus, the charge balance in the PIC micelles shifted to decrease the core density owing to the electrostatic repulsions of the excess cations in the core. The PIC micelles dissociated at a NaCl concentration ≥0.6 M owing to the charge screening effect. The positively charged PIC micelles with excess P100M98 can encapsulate anionic dyes owing to electrostatic interaction.

Synergetic Regulation of Interface Defects and Carriers Dynamics for High-Performance Lead-Free Perovskite Solar Cells.

Severe nonradiative recombination and open-circuit voltage loss triggered by high-density interface defects greatly restrict the continuous improvement of Sn-based perovskite solar cells (Sn-PVSCs). Herein, a novel amphoteric semiconductor, O-pivaloylhydroxylammonium trifluoromethanesulfonate (PHAAT), is developed to manage interface defects and carrier dynamics of Sn-PVSCs. The amphiphilic ionic modulators containing multiple Lewis-base functional groups can synergistically passivate anionic and cationic defects while coordinating with uncoordinated Sn2+ to compensate for surface charge and alleviate the Sn2+ oxidation. Especially, the sulfonate anions raise the energy barrier of surface oxidation, relieve lattice distortion, and inhibit nonradiative recombination by passivating Sn-related and I-related deep-level defects. Furthermore, the strong coupling between PHAAT and Sn perovskite induces the transition of the surface electronic state from p-type to n-type, thus creating an extra back-surface field to accelerate electron extraction. Consequently, the PHAAT-treated device exhibits a champion efficiency of 13.94% with negligible hysteresis. The device without any encapsulation maintains 94.7% of its initial PCE after 2000h of storage and 91.6% of its initial PCE after 1000h of continuous illumination. This work provides a reliable strategy to passivate interface defects and construct p-n homojunction to realize efficient and stable Sn-based perovskite photovoltaic devices.

Electrically Redox-Active Membrane with Switchable Selectivity to Contaminants for Water Purification.

Membrane technology provides an attractive approach for water purification but faces significant challenges in separating small molecules due to its lack of satisfactory permselectivity. In this study, a polypyrrole-based active membrane with a switchable multi-affinity that simultaneously separates small ionic and organic contaminants from water was created. Unlike conventional passive membranes, the designed membrane exhibits a good single-pass filtration efficiency (>99%, taking 1-naphthylamine and Pb2+ as examples) and high permeability (227 L/m2/h). Applying a reversible potential can release the captured substances from the membrane, thus enabling membrane regeneration and self-cleaning without the need for additives. Advanced characterizations reveal that potential switching alters the orientation of the doped amphipathic molecules with the self-alignment of the hydrophobic alkyl chains or the disordered sulfonate anions to capture the target organic molecules or ions via hydrophobic or electrostatic interactions, respectively. The designed smart membrane holds great promise for controllable molecular separation and water purification.

Degradable Poly(styrene sulfonate) Polyanions for Biomedical and Electrochemical Applications

AbstractThe synthesis of poly(styrene sulfonate) with hydrolysable ester groups in the main chain is reported. The material is obtained by free radical copolymerization of either styrene sulfonate sodium salt (SSNa) or styrene sulfonate alkyl esters (SSA) with the cyclic ketene acetal 2‐methylen‐1,3,6‐trioxocane (MTC). As for other systems made from cyclic ketene acetals, the reactions are difficult to control and give copolymers with high polydispersity index. MTC homopolymer is obtained as a side product in both cases. Thermal cleavage of the alkyl protective groups of the poly(styrene sulfonate alkyl esters) to obtain the target polystyrene sulfonate anions remains incomplete. Thus, direct synthesis of the polyanion from SSNa and MTC is the more efficient process, especially since the poly(SSNa‐co‐MTC) copolymer can be easily separated from MTC homopolymer. 1H‐NMR analytics indicates MTC repeat unit contents of 2–11%, depending on the initial SSNa to MTC ratio. The MTC ester groups of the copolymers are hydrolyzed in aqueous conditions, with and without enzyme, and a marked decrease in the molar mass is observed after hydrolysis. This confirms that these copolymers have the designed intended break points in the main chain, and could become a part of fully degradable electroactive polymer systems.

The effect of anionic surfactant type and concentration on the development of waterborne nitrocellulose

To better understand the gel emulsification method as an efficient method for producing waterborne nitrocellulose coatings [1–3], the effect of anionic surfactant type (sodium dodecyl sulfate (SDS) and sodium dodecyl benzene sulfonate (SDBS)) and concentration on the emulsification process was investigated. In the case of using SDBS, it was not possible to produce nitrocellulose emulsion via the gel emulsification method while emulsions with submicron size were produced using SDS. Contrary to what might be thought, in the gel emulsification method, high surfactant concentrations did not contribute to better drop breakage and led to catastrophic phase inversion. In addition, increasing surfactant concentration increased the hydrophilicity of the final coatings and decreased their chemical and mechanical properties.

Molecular dynamics simulation of surfactant induced wettability alteration of shale reservoirs

Shale oil has recently received considerable attention as a promising energy source due to its substantial reserves. However, the recovery of shale oil presents numerous challenges due to the low-porosity and low-permeability characteristics of shale reservoirs. To tackle this challenge, the introduction of surfactants capable of modifying wettability has been employed to enhance shale oil recovery. In this study, we perform molecular dynamics simulations to investigate the influence of surfactants on the alteration of wettability in shale reservoirs. Firstly, surfaces of kaolinite, graphene, and kerogen are constructed to represent the inorganic and organic constituents of shale reservoirs. The impact and underlying mechanisms of two types of ionic surfactants, namely, the anionic surfactant sodium dodecylbenzene sulfonate (SDBS) and cationic surfactant dodecyltrimethylammonium bromide (DTAB), on the wettability between oil droplets and surfaces are investigated. The wettability are analyzed from different aspects, including contact angle, centroid ordinates, and self-diffusion coefficient. Simulation results show that the presence of surfactants can modify the wetting characteristics of crude oil within shale reservoirs. Notably, a reversal of wettability has been observed for oil-wet kaolinite surfaces. As for kerogen surfaces, it is found that an optimal surfactant concentration exists, beyond which the further addition of surfactant may not enhance the efficiency of wettability alteration.

Do Melamine and Melamine-Formaldehyde Surface Modifiers Improve Fuel Cell Activity and Durability?

Precious group metal-based catalysts based on Pt- and Pt-alloys are currently used as catalysts for the kinetically sluggish Oxygen Reduction Reaction (ORR) on the cathode of fuel cells. The activity of Pt or Pt-alloy catalysts towards ORR is severely compromised by the adsorption of spectator-species such as sulfonate anions from perfluorosulfonic acid (PFSA) ionomer or Pt-O(H)ad via water activation. Considering recent evidence pointing to the improvement in ORR activity via the use of melamine organic molecule or melamine-formaldehyde copolymeric additives as surface blocking agents for the prevention of sulfonate or Pt-OHad adsorption, we evaluated these additives in fuel cells. The catalysts were modified with either of these additives and characterized using ex situ and in situ methods to verify successful adsorption and eventual performance in fuel cells. These surface modifying agents were found to suppress Pt-OHad formation as well as suppress ORR activity. There was no evidence to point out that these additives improved ORR activity and H2/air polarization performance in a fuel cell MEA on supported, polycrystalline Pt catalyst.

Complexes of an Anionic Surfactant with Chitosan and Its Hydrophobic Derivatives As Disinfectants against SARS-CoV-2

This work is aimed at the preparation of complexes of chitosan and hydrophobically modified (HM) chitosan with an anionic surfactant sodium dodecylbenzene sulfonate (SDBS), and at the study of the virucidal activity of the complexes and their components against SARS-CoV-2. It is shown that the introduction of a sufficient amount (4 mol%) of hydrophobic n-dodecyl side groups provides the activity of HM chitosan against SARS-CoV-2 at moderate concentrations, at which unmodified chitosan and chitosan containing a lower amount of hydrophobic groups do not show any activity. Complexes of HM chitosan with SDBS are prepared, which is proven by fluorescence spectroscopy and isothermal titration calorimetry. It is discovered that HM chitosan/SDBS complex is more active than the polymer without surfactant, and an increase of the amount of hydrophobic groups enhances the activity

A novel PVA/MWCNTs hydrogel with high toughness and electromagnetic shielding properties

AbstractCarbon nanotubes (CNTs) are widely utilized as conductive fillers due to their high conductivity, lightweight, and ease of modification. However, their poor dispersion limits their otherwise excellent performance. In this study, we successfully prepared a high toughness, strong electromagnetic interference (EMI) shielding hydrogel by blending polyvinyl alcohol (PVA) hydrogel with multi‐walled carbon nanotubes (MWCNTs) modified by anionic surfactant sodium dodecylbenzene sulfonate (SDBS) and (3‐aminopropyl) triethoxysilane (KH550). We found that the modifiers can not only promote the uniform dispersion of MWCNTs but also improve the mechanical properties of the hydrogel. The results demonstrate that the stress (≈14.86 MPA), elongation at break (233.9%), and compressive strength (≈2.89 MPA) of PVA/MWCNTs composite hydrogel with 1 wt% MWCNTs and 5 wt% PVA were increased by 533.6%, 241.4%, and 206.5%, respectively. Encouragingly, the total electromagnetic shielding effectiveness (SET) is 123.6 dB at a thickness of 5 mm. In summary, this work provides a general approach to functionalizing MWCNTs, which has great potential for developing EMI shielding materials with high toughness.

Controlled Self-Assembly, Isomerism, and Guest Uptake/Release of Charge-Reversible Lanthanide-Organic Octahedral Cages.

Charge plays a crucial role in the function of molecular and supramolecular systems, but coordination hosts capable of orthogonal charge regulation remain elusive so far. In this study, we report the condition-dependent self-assembly of charge-reversible lanthanide-organic tetra-capped octahedral cages, i.e., [Ln6(H3L)4]6+ and [Ln6L4]6-, from a series of lanthanide ions (Ln3+; Ln = Lu, Yb, Eu) and a tritopic tetradentate acylhydrazone ligand (H6L) featuring multiple deprotonation states and propeller conformations. While direct self-assembly under basic conditions produced a mixture of various ΔxΛ6-x-[Ln6L4]6- (x = 0-6) stereoisomers, racemic Δ6- and Λ6-[Ln6L4]6- could be exclusively obtained from the first self-assembly of Δ6- and Λ6-[Ln6(H3L)4]6+ under neutral conditions followed by post-assembly deprotonation. Rich isomerism on the tetra-capped octahedral cages arising from the coupling between the metal-centered Δ/Λ chirality and the ligand conformations has been discussed based on X-ray single-crystal structures of the C3-symmetric Δ3Λ3-Ln6L4 and T-symmetric Δ6/Λ6-Ln6L4 complexes. Host-guest studies confirmed that positively charged rac-Δ6/Λ6-[Ln6(H3L)4]6+ could bind anionic sulfonates, and negatively charged rac-Δ6/Λ6-[Ln6L4]6- exhibited strong encapsulation ability toward ammonium guests, where acid/base-triggered guest uptake/release could be realized taking advantage of the charge reversibility of the cage. Moreover, photophysical studies revealed visible-light-sensitized and guest-encapsulation-enhanced NIR emissions on the rac-Δ6/Λ6-Yb6L4 cage. This work not only enriches the library of functional lanthanide-organic cages but also provides a promising candidate with charge reversibility for the development of smart supramolecular materials.

Study on the synergistic effect of the binary compound system of cardanol sulfonate

Abstract In the present work, the anionic biomass surfactant cardanol sulfonate (CDS) was compounded in different molar fractions (α 1) with the commonly used amphoteric surfactant lauryl amidopropyl betaine (LAB) and the nonionic surfactant alkyl glycoside (APG), respectively. By measuring the surface tension of the binary compound system, the relationship between the surface chemical properties of the compound system and α 1 was investigated, and then the synergistic parameters and thermodynamic parameters of the compound system were calculated. The results showed that both CDS/LAB and CDS/APG systems exhibited non-ideal mixing behavior. The CDS/LAB compound system has the best synergistic effect when the two components were mixed in a 1:1 molar ratio, corresponding to a CMC of 3.06 × 10−4 mol L−1 and a γ CMC of 32.60 mN m−1. The formation of mixed micelles was a spontaneous exothermic process driven by enthalpy. The CDS/APG compound system at the molar ratio of n(APG): n(CDS) = 9:1 has a more significant synergistic effect, corresponding to a CMC of 1.13 × 10−4 mol L−1 and a γ CMC of 29.10 mN m−1. The application performance of the compound systems was the best at the optimal molar ratio, which confirms the existence of synergistic effect in the compound systems.

Transport of polystyrene nanoplastics in porous media: Combined effects of two co-existing substances

Both surfactants and natural organic matters (NOMs) are substances commonly found in aqueous environments, and their effects on the transport of nanoplastics that is gradually gaining widespread attention in porous media are currently in their infancy, while their combined effects are absent. We investigated innovatively the combined effect of surfactants and NOMs on the transport of polystyrene nanoplastics (PS-NPs) in saturated porous media. Adsorption tests of surfactants and NOMs onto PS-NPs, adsorption tests of PS-NPs onto quartz sand, and transport tests of PS-NPs in saturated quartz sand were conducted. Hydrophobicity and Derjaguin-Landau-Verwey-Overbeek (DLVO) interaction energy were measured and calculated. A mathematical model was employed to fit the transport of PS-NPs in porous media. It was found that the effects and action mechanisms of cationic cetyl trimethylammonium bromide (CTAB) and anionic sodium dodecylbenzene sulfonate (SDBS) on the transport of PS-NPs in porous media were distinct. In the presence of CTAB, 1 mg/L humic acid (HA) and 10 mg/L sodium alginate (SA) could promote aggregation of PS-NPs by decreasing the absolute zeta potential of PS-NPs, and reducing the energy barrier between PS-NPs and porous media and increasing the blocking and straining, thus inhibiting the transport of PS-NPs. In the presence of SDBS, SA and HA could improve the adsorption of SDBS onto PS-NPs by bridging and increasing adsorption sites, thus increasing the hydrophilicity of PS-NPs and improving the transport of PS-NPs. Whether or not NOMs were present, the transport of PS-NPs in porous media was mainly governed by the DLVO interaction energy in the presence of cationic surfactants and by hydrophobicity in the presence of anionic surfactants. This innovative observation has led to an understanding on the environmental behaviour of nanoplastics in porous media under complex environments.

Fabrication and Training of 3D Conductive Polymer Networks for Neuromorphic Wetware

AbstractThe human brain possesses an exceptional information processing capability owing to the 3D and dense network architecture of numerous neurons and synapses. Brain‐inspired neuromorphic hardware can also benefit from 3D architectures, such as high integration of circuits and acquisition of highly complex dynamical systems. In this study, for future 3D neuromorphic engineering, 3D conductive polymer networks consisting of poly(3,4‐ethylenedioxy‐thiophene) doped with poly(styrene sulfonate) anions (PEDOT:PSS) are successfully and stably fabricated between multiple electrodes from scratch in precursor solution by electropolymerization. The networks efficiently emulate the 3D local connections between neighboring neurons observed in the cortex. This novel technology, which allows 3D conductive wiring only between desired electrodes, is unprecedented and has potential as an underlying technology for 3D integration. Furthermore, the experimental results also conclusively prove that conductance modification can be performed by manipulating the physical and chemical properties of 3D branch‐wired conductive polymer wires, thus demonstrating for the first time the feasibility of neuromorphic wetware with enhanced biological plausibility in the subsequent post‐Moore era.

Effects and mechanisms of different types of surfactants on sapphire ultrasonic polishing

The effects of three different types of surfactants, including cationic surfactant cetyltrimethylammonium bromide (CTAB), anionic surfactant sodium dodecyl benzene sulfonate (SDBS), and nonionic surfactant fatty alcohol polyoxyethylene ether (AEO), on sapphire ultrasonic polishing (UV-CMP) were studied. Through XPS, SEM, surface tension, zeta potential and particle size analysis, the implications of surfactants on the chemical products, abrasive adsorption, and material removal rate (MRR) of sapphire surface were investigated. The findings indicate that AEO and SDBS result in a certain degree of abrasive agglomeration and slight particle size increase due to hydrogen bonding and electrostatic repulsion respectively. The cationic surfactant CTAB exhibits significant agglomeration of abrasive particles due to electrostatic attraction, and causes the increase in particle size. The slurry’s surface tension is directly proportional to sapphire MRR within a certain range. The polishing effects are the best when 0.10% CTAB is added. Sapphire MRR is 80.50 nm/min, which is nearly twice as much as that of the slurry without surfactants. The surface roughness is 0.200 nm after polishing.