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Minimizing electrostatic interactions from piezoresponse force microscopy via capacitive excitation

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Theoretical & Applied Mechanics Letters 2020年第1期10卷 23-26页

作者： Qingfeng Zhu Ehsan Nasr Esfahani Shuhong Xie Jiangyu Li Shenzhen Key Laboratory of Nanobiomechanics Shenzhen Institutes of Advanced TechnologyChinese Academy of SciencesShenzhen 518055China Hunan Provincial Key Laboratory of Thin Film Materials and Devices Xiangtan UniversityXiangtan 411105China Department of Mechanical Engineering University of WashingtonSeattle 98195WAUSA Key Laboratory of Low Dimensional Materials and Application Technology of Ministry of Education and School of Materials Science and EngineeringXiangtan UniversityXiangtan 411105China

Piezoresponse force microscopy(PFM)has emerged as one of the most powerful techniques to probe ferroelectric materials at the nanoscale,yet it has been increasingly recognized that piezoresponse measured by PFM is often influenced by electrostatic interactions.In this letter,we report a capacitive excitation PFM(ce-PFM)to minimize the electrostatic interactions.The effectiveness of ce-PFM in minimizing electrostatic interactions is demonstrated by comparing the piezoresponse and the effective piezoelectric coefficient measured by ce-PFM and conventional PFM.The effectiveness is further confirmed through the ferroelectric domain pattern imaged via ce-PFM and conventional PFM in vertical modes,with the corresponding domain contrast obtained by ce-PFM is sharper than conventional PFM.These results demonstrate ce-PFM as an effective tool to minimize the interference from electrostatic interactions and to image ferroelectric domain pattern,and it can be easily implemented in conventional atomic force microscope(AFM)setup to probe true piezoelectricity at the nanoscale.

关键词： Piezoresponse force microscopy electrostatic interactions Capacitive excitation

Recent progress in polymerization-induced self-assembly:From the perspective of driving forces

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Aggregate 2024年第1期5卷 47-66页

作者： Zizhuo Zhao Shujing Lei Min Zeng Meng Huo Department of Chemistry Key Laboratory of Surface and Interface Science of Polymer Materials of Zhejiang ProvinceZhejiang Sci-Tech UniversityHangzhouP.R.China Department of Chemistry University of WarwickCoventryUK

Polymerization-induced self-assembly(PISA)enables the simultaneous growth and self-assembly of block copolymers in one pot and therefore has developed into a high-efficiency platform for the preparation of polymer assemblies with high concentration and excellent reproducibility.During the past decade,the driving force of PISA has extended from hydrophobic interactions to other supramolecular interactions,which has greatly innovated the design of PISA,enlarged the monomer/solvent toolkit,and endowed the polymer assemblies with intrinsic dynamicity and responsiveness.To unravel the important role of driving forces in the formation of polymeric assemblies,this review summarized the recent development of PISA from the perspective of driving forces.Motivated by this goal,here we give a brief overview of the basic principles of PISA and systematically discuss the various driving forces in the PISA system,including hydrophobic interactions,hydrogen bonding,electrostatic interactions,andπ-πinteractions.Furthermore,PISA systems that are driven and regulated by crystallization or liquid crystalline ordering were also highlighted.

关键词： driving forces electrostatic interactions hydrogen bonding hydrophobic interactions polymerizationinduced self-assembly

Porous Assembly of Metallo-Supramolecule and Polyoxometal-ate via Ionic Complexation with Vapor Sorption Properties

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Chinese Journal of Chemistry 2022年第7期40卷 813-818页

作者： Yaping Xu Hao Yu Xin Jiang Junjuan Shi Bao Li Lu Li Lixin Wu Ming Wang State Key Laboratory of Supramolecular Structure and Materials College of ChemistryJilin UniversityChangchunJilin 130012China State Key Laboratory of Inorganic Synthesis and Preparative Chemistry College of ChemistryJilin UniversityChangchunJilin 130012China

Porous materials have been extensively developed and displayed special applications in diverse fields,however,it still remains a great challenge in developing new synthetic methods with features of energy-saving and easy-operating.In this study,we reported the construction of a series of novel ionic complexes based on discrete supramolecular triangle structure and polyoxometalate[Mo_(6)O_(19)]^(2-),using a quite efficient strategy.The obtained composites exhibit precise 3D network structures with ideal stability con-taining micropores,which were characterized by the 1H NMR,ESI-MS,TEM,SEM,and single-crystal X-ray diffraction.These compo-sites showed differential vapor adsorption behaviors for benzene,toluene,and cyclohexane.This work provides a novel approach for fabricating porous materials through electrostatic interactions and has great potential for gas separation.

关键词： Self-assembly Metallo-supramolecule Polyoxometalates electrostatic interactions Vapor sorption

Halogen Bond Catalysis on Carbonyl-Olefin Ring-Closing Metathesis Reaction:Comparison with Lewis Acid Catalysis

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Chinese Journal of Chemistry 2022年第11期40卷 1275-1284页

作者： Ying Li Yuanyuan Sun Lingpeng Meng Qingzhong Li Yanli Zeng College of Chemistry and Materials Science Hebei Key Laboratory of Inorganic Nano-materialsHebei Normal UniversityShijiazhuangHebei 050024China The Laboratory of Theoretical and Computational Chemistry College of Chemistry&Chemical EngineeringYantai UniversityYantaiShandong 264005China

The carbonyl-olefin ring-closing metathesis reactions have become a powerful tool for carbon-carbon bond formation.In this work,the halogen bond catalysis and classical Lewis acid catalysis on the carbonyl-olefin ring-closing metathesis reaction were investigated by density function theory.For both the halogen bond catalysis and classical Lewis acid catalysis,the carbonyl-olefin ring-closing me-tathesis reaction occurs by[2+2]-cycloaddition process and[2+2]-cycloreversion process,the reaction energy barriers are low,there-fore,it can be performed easily at room temperature.The essential difference of the two kinds of catalysts is that the catalytic mecha-nism of halogen bond catalysis is mainly contribution of electrostatic interaction,while that of classical Lewis acid catalysis is mainly catalyzed by orbital interaction.The halogen bond donor catalysts(ICI_(3),IF_(3))are expected to be efficient catalysts for the reaction and further promote the chemical synthesis of carbonyl-olefin ring-closing metathesis reaction.

关键词： Halogen bond donors Lewis acids electrostatic interactions Orbital interaction Carbonyl-olefin ring-closing metathesis

Block Copolymer Solid Electrolytes Based on Comb-Like Poly(ethylene glycol)Plasticized Poly(ionic liquid)s for Lithium-Ion Batteries

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Chinese Journal of Chemistry 2023年第19期41卷 2493-2501页

作者： Runtao Zhao Jixing Yang Bin Wang Zhe Ma Li Pan Yuesheng Li School of Materials Science and Engineering Tianjin Key Laboratory of Composite and Functional MaterialsTianjin UniversityTianjin300072 China

Electrolytes based on poly(ionic liquid)s(PILs)have attracted great attention in the fields of next-generation solid lithium-ion batteries.However,the low ionic conductivity prevents their practical applications.Herein,we report novel solid electrolytes based on block copolymers composed of PILs and comb-like poly(ethylene glycol)(PEG),which were synthesized via ring-opening metathesis polymerization of 3-(2-(bicyclo[2.2.1]hept-5-en-2-yl)ethyl)-1-butyl-1H-imidazol-3-ium bis((trifluoromethyl)sulfonyl)amide and poly(ethylene glycol monomethyl ether)bicyclo[2.2.1]hept-5-ene-2-carboxylate.Comb-like PEG acts as plasticizers in block copolymers dominated by PILs to promote the mobility of PILs segments.Effects of the copolymer composition and length of the comb-like PEG chain on ionic conductivity were investigated.The optimized electrolyte delivers the highest ionic conductivity of 1.5×10^(–5)S·cm^(–1)at 30℃,and robust electrochemical stability up to 4.6 V.A solid-state Li/LiFePO4 cell using the optimized electrolyte demonstrates good cycle performance at 0.2 C with high capacity retention of 92%after 70 cycles at 50℃.

关键词： Solid polymer electrolytes Li-ion batteries Polymerized ionic liquids Poly(ethylene glycol) Block copolymers electrostatic interactions

A novel aminated polymeric adsorbent for removing refractory dissolved organic matter from landfill leachate treatment plant

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Journal of Environmental Sciences 2009年第8期21卷 1089-1095页

作者： ZHANG Long, LI Aimin, WANG Jinnan, LU Yufei, ZHOU Youdong State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210093, China. State Key Laboratory of Pollution Control and Resource Reuse School of the Environment Nanjing University Nanjing 210093 China

Refractory dissolved organic matter （DOM） from landfill leachate treatment plant was with high dissolved organic carbon （DOC） content. An aminated polymeric adsorbent NDA-8 with tertiary amino groups and sufficient mesopore was synthesized, which exhibited high adsorption capacity to the DOM （raw water after coagulation）. Resin NDA-8 performed better in the uptake of the DOM than resin DAX-8 and A100. electrostatic attraction was considered as the decisive interaction between the adsorbent and adsorbate. Special attention was paid to the correlation between porous structure and adsorption capacity. The mesopore of NDA-8 played a crucial role during uptake of the DOM. In general, resin in chloride form performed a higher removal rate of DOC. According to the colunm adsorption test, total adsorption capacity of NDA-8 was calculated to 52.28 mg DOC/mL wet resin. 0.2 mol/L sodium hydroxide solution could regenerate the adsorbent efficiently.

关键词： electrostatic interactions chemically modified resin coagulation adsorption pore structure

Nerve conduction models in myelinated and unmyelinated nerves based on three-dimensional electrostatic interaction

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Neural Regeneration Research 2018年第5期13卷 779-785页

作者： Tetsuya Akaishi Department of Neurology Tohoku University Graduate School of Medicine Department of Neurology Yonezawa National Hospital

Until now, nerve conduction has been described on the basis of equivalent circuit model and cable theory, both of which supposed closed electric circuits spreading inside and outside the axoplasm. With these conventional models, we can simulate the propagating pattern of action potential along the axonal membrane based on Ohm＇s law and Kirchhoff＇s law. However, we could not fully explain the different conductive patterns in unmyelinated and myelinated nerves with these theories. Also, whether we can really suppose closed electrical circuits in the actual site of the nerves or not has not been fully discussed yet. In this report, a recently introduced new theoretical model of nerve conduction based on electrostatic molecular interactions within the axoplasm will be reviewed. With this new approach, we can explain the different conductive patterns in unmyelinated and myelinated nerves. This new mathematical conductive model based on electrostatic compressional wave in the intracellular fluid may also be able to explain the signal integration in the neuronal cell body and the back-propagation mechanism from the axons to the dendrites. With this new mathematical nerve conduction model based on electrostatic molecular interactions within the intracellular fluid, we may be able to achieve an integrated explanation for the physiological phenomena taking place in the nervous system.

关键词： nerve conduction ion channels electrostatic interactions electrostatic compressional wave saltatory conduction myelinated nerves unmyelinated nerves saltatory equations

Review of characterization and modeling of polymer electrolyte fuel cell catalyst layer： The blessing and curse of ionomer

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Frontiers in Energy 2017年第3期11卷 334-364页

作者： Jun HUANG Zhe LI Jianbo ZHANG Department of Automotive Engineering State Key Laboratory of Automotive Safety and Energy Tsinghua University Beijing 100084 China College of Chemistry and Chemical Engineering Central South University Changsha 410083 China Beijing Co-innovation Center for Electric Vehicles Beijing Institute of Technology Beijing 100081 China

Ionomer impregnation represents a milestone in the evolution of polymer electrolyte fuel cell （PEFC） catalyst layers. Ionomer acts as the binder, facilitates proton transport, and thereby drastically improves catalyst utilization and effectiveness. However, advanced morpho- logical and functional characterizations have revealed that up to 60% of Pt nanoparticles can be trapped in the micropores of carbon support particles. Ionomer clusters and oxygen molecules can hardly enter into micropores, leading to low Pt utilization and effectiveness. Moreover, the ionomer thin-films covering Pt nanoparticles can cause significant mass transport loss especially at high current densities. Ionomer-free ultra-thin catalyst layers （UTCLs） emerge as a promising alternative to reduce Pt loading by improving catalyst utilization and effectiveness, while theoretical issues such as the proton conduction mechan- ism remain puzzling and practical issues such as the rather narrow operation window remain unsettled. At present, the development of PEFC catalyst layer has come to a crossroads： staying ionomer-impregnated or going iono- mer-free. It is always beneficial to look back into the past when coming to a crossroads. This paper addresses the characterization and modeling of both the conventional ionomer-impregnated catalyst layer and the emerging ionomer-free UTCLs, featuring advances in characterizing microscale distributions of Pt particles, ionomer, support particles and unraveling their interactions; advances in fundamental understandings of proton conduction and flooding behaviors in ionomer-free UTCLs; advances in modeling of conventional catalyst layers and especially UTCLs; and discussions on high-impact research topics in characterizing and modeling of catalyst layers.

关键词： polymer electrolyte fuel cell ultra-thin cata-lyst layer electrostatic interactions characterization andmodeling structure-property-performance relation watermanagement

Flame-retardant and Self-healing Biomass Aerogels Based on electrostatic Assembly

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Chinese Journal of Polymer Science 2020年第12期38卷 1294-1304页

作者： Ji-Yu Yang Yu Xia Jin Zhao Long-Fei Yi Yong-Jiao Song Hong Wu Shao-Yun Guo Li-Juan Zhao Jin-Rong Wu College of Chemistry and Materials Science Sichuan Normal UniversityChengdu 610066China State Key Laboratory ofPolymer Materials Engineering Polymer Research InstituteSichuan UniversityChengdu 610065China State Key Laboratory ofPolymer Materials Engineering Collegeof Polymer Science and EngineeringSichuan UniversityChengdu 610065China

It remains a significant challenge to fabricate self-healing aerogels with excellent flame retardancy.Herein,we develop a class of biomass aerogels by electrostatically assembling chitosan(CS),phytic acid(PA),and itaconic acid(IA).The electrostatic interaction between CS and IA is weak and dynamic,so freeze-drying the solution of CS and IA enables the formation of continuous aerogel skeleton with self-healing ability and re-programmability;in comparison,the electrostatic interaction between CS and PA is strong and less dynamic,and thus mixing PA with CS in aqueous solution leads to fine precipitates of high flame retardancy due to the synergistic phosphorus-nitrogen effect.Integrating the continuous skeleton and the fine precipitates results in self-healing aerogles with UL-4 V-0 rating of flame retardancy aerogels and autoextinguishable feature.Interestingly,the aerogels after burning in flame for 30 s form a skin-core structure,and the carbonized skin protects the integrity of the aerogels and the self-healing ability of the internal parts.Therefore,this work provides a facile strategy to develop multifunctional aerogels which hold great promise for advanced applications.

关键词： Chitosan Flame retardancy electrostatic interactions Biomass aerogel Self-healing