Characteristics of Aerosol Ionic Compositions in Summer 2003 at Lin'an of Yangtze Delta Region

With the size-resolved aerosol mass and ion composition data obtained at Lin＇an regional atmospheric pollution monitoring station in July 2003, the size distributions of aerosol mass and ionic components, and the correlations between major ion pairs were analyzed. The primary results indicate that in the period of in-situ measurement, the aerosols are mainly composed of fine particles. The mass of aerosols with size less than 2.1 μm accounts for 66% of the total mass of all size ranges, in which about 50% of the mass is contributed by the particles with size less than 0.65 μm. Similar to the size distributions of aerosol mass, the water-soluble ions are mainly concentrated in the size range of 〈0.65 μm, accounting for about 77% of the sum of analyzed ions, and the ions within the range of 〈2.1 μm reach 88%. The sulfate, ammonium, and potassium are the dominant ionic components in fine particles （particle size less than 2.1 μm）. Ion correlation analysis suggests that the sulfates in fine particles are mostly in the compounds of （NH4）2SO4, Na2SO4, and K2SO4, but for submicron particles the sulfates are mainly in the form of （NH4）2SO4.

Enabling high-performance all-solid-state lithium batteries with high ionic conductive sulfide-based composite solid electrolyte and ex-situ artificial SEI film

All-solid-state lithium batteries(ASSLBs) employing sulfide electrolyte and lithium(Li) anode have received increasing attention due to the intrinsic safety and high energy density.However,the thick electrolyte layer and lithium dendrites formed at the electrolyte/Li anode interface hinder the realization of high-performance ASSLBs.Herein,a novel membrane consisting of Li_(6)PS_(5) Cl(LPSCl),poly(ethylene oxide)(PEO) and Li-salt(LiTFSI) was prepared as sulfide-based composite solid electrolyte(LPSCl-PEO3-LiTFSI)(LPSCl:PEO=97:3 wt/wt;EO:Li=8:1 mol/mol),which delivers high ionic conductivity(1.1 × 10^(-3) S cm^(-1)) and wide electrochemical window(4.9 V vs.Li^(+)/Li) at 25 ℃.In addition,an ex-situ artificial solid electrolyte interphase(SEI) film enriched with LiF and Li3 N was designed as a protective layer on Li anode(Li(SEI)) to suppress the growth of lithium dendrites.Benefiting from the synergy of sulfide-based composite solid electrolyte and ex-situ artificial SEI,cells of S-CNTs/LPSCI-PEO3-LiTFSI/Li(SEI) and Al_(2)O_(3)@LiNi_(0.5)Co_(0.3)Mn_(0.2)O_(2)/LPSCl-PEO3-LiTFSI/Li(SEI) are assembled and both exhibit high initial discharge capacity of 1221.1 mAh g^(-1)(135.8 mAh g^(-1)) and enhanced cycling stability with 81.6% capacity retention over 200 cycles at 0.05 C(89.2% over 100 cycles at 0.1 C).This work provides a new insight into the synergy of composite solid electrolyte and artificial SEI for achieving high-performance ASSLBs.

Experimental study and electromechanical model analysis of the nonlinear deformation behavior of IPMC actuators

This paper develops analytical electromechanical formulas to predict the mechanical deformation of ionic polymer-metal composite (IPMC) cantilever actuators under DC excitation voltages. In this research, IPMC samples with Pt and Ag electrodes were manufactured, and the large nonlinear deformation and the effect of curvature on surface electrode resistance of the IPMC samples were investigated experimentally and theoretically. A distributed electrical model was modified for calculating the distribution of voltage along the bending actuator. Then an irreversible thermodynamic model that could predict the curvature of a unit part of an IPMC actuator is combined with the electrical model so that an analytical electromechanical model is developed. The electromechanical model is then validated against the experimental results obtained from Pt- and Ag-IPMC actuators under various excitation voltages. The good agreement between the electromechanical model and the actuators shows that the analytical electromechanical model can accurately describe the large nonlinear quasi-static deflection behavior of IPMC actuators.

Recent research progress on quasi-solid-state electrolytes for dye-sensitized solar cells

Dye-sensitized solar cells （DSSCs） are the most promising, low cost and most extensively investigated solar cells. They are famous for their clean and efficient solar energy conversion. Nevertheless this, long-time sta- bility is still to be acquired. In recent years research on solid and quasi-solid state electrolytes is extensively in- creased. Various quasi-solid electrolytes, including composites polymer electrolytes, ionic liquid electrolytes, thermoplastic polymer electrolytes and thermosetting polymer electrolytes have been used. Performance and stability of a quasi-solid state electrolyte are between liquid and solid electrolytes. High photovoltaic performances of QS-DSSCs along better long-term stability can be obtained by designing and optimizing quasi-solid electrolytes. It is a prospective candidate for highly efficient and stable DSSCs.

Advanced Electro-active Dry Adhesive Actuated by an Artificial Muscle Constructed from an Ionic Polymer Metal Composite Reinforced with Nitrogen-doped Carbon Nanocages

An advanced electro-active dry adhesive, which was composed of a mushroom-shaped tibrillar dry adhesive array actuated by an Ionic Polymer Metal Composite （IPMC） artificial muscle reinforced with nitrogen-doped carbon nanocages （NCNCs）, was developed to imitate the actuation of a gecko＇s toe. The properties of the NCNC-reinforced Nation membrane, the electro- mechanical properties of the NCNC-reinforced IPMC, and the related electro-active adhesion ability were investigated. The NCNCs were uniformly dispersed in the 0.1 wt% NCNC/Nafion membrane, and there was a seamless connection with no clear interface between the dry adhesive and the IPMC. Our 0.1 wt% NCNC/Nation-IPMC actuator shows a displacement and force that are 1.6 - 2 times higher than those of the recast Nafion-IPMC. This is due to the increased water uptake （25.39%） and tensile strength （24.5 MPa） of the specific 3D hollow NCNC-reinforced Nation membrane, as well as interactions between the NCNCs and the sulfonated groups of the Nation. The NCNC/Nation-IPMC was used to effectively actuate the mushroom-shaped dry adhesive. The normal adhesion forces were 7.85 raN, 12.1 mN, and 51.7 mN at sinusoidal voltages of 1.5 V, 2.5 V, and 3.5 V, respectively, at 0.1 Hz. Under the bionic leg trail, the normal and shear forces were approximately 713.5 mN （159 mN·cm^-2） and 1256.6 mN （279 mN·cm^-2）, respectively, which satisfy the required adhesion. This new electro-active dry adhesive can be applied for active, distributed actuation and flexible grip in robots.

Bio-inspired robotic manta ray powered by ionic polymer-metal composite artificial muscles

The manta ray(Manta birostris)is the largest species of rays that demonstrates excellent swimming capabilities via large-amplitude flapping of its pectoral fins.In this article,we present a bio-inspired robotic manta ray using ionic polymer–metal composite(IPMC)as artificial muscles to mimic the swimming behavior of the manta ray.The robot utilizes two artificial pectoral fins to generate undulatory flapping motions,which produce thrust for the robot.Each pectoral fin consists of an IPMC muscle in the leading edge and a passive polydimethylsiloxane membrane in the trailing edge.When the IPMC is actuated,the passive polydimethylsiloxane membrane follows the bending of the leading edge with a phase delay,which leads to an undulatory flapping motion on the fin.Characterization of the pectoral fin has shown that the fin can generate flapping motions with up to 100%tip deflection and 40◦twist angle.To test the free-swimming performance of the robot,a light and compact on-board control unit with a lithium ion polymer battery has been developed.The experimental results have shown that the robot can swim at 0.067 BL/s with portable power consumption of under 2.5 W.

A Gradient Model for Young's Modulus and Surface Electrode Resistance of Ionic Polymer-Metai Composite

A new model is proposed to estimate Young's modulus and surface electrode resistance of the ionic polymer-metai composite(IPMC)with a gradient distribution of micros true ture.The entire IPMC electrode is divided into two parts,i.e.,the porous metal electrode and the gradient polymer-metai composite electrode,according to the geometrie properties of the electroless plated metal electrode.The validity and accuracy of the model are justified by comparing with the experimental observations of IPMC samples.The differences between model predictions and experimental data of Young's modulus and surface resistance of IPMC samples are+6.8%and-5.5%,respectively,indicating a reasonably good agreement.

Review on Improvement,Modeling,and Application of Ionic Polymer Metal Composite Artificial Muscle

Recently,researchers have concentrated on studying ionic polymer metal composite(IPMC)artificial muscle,which has numerous advantages including a relatively large strain under low input voltage,flexibility,high response,low noise,light weight,and high driving energy density.This paper reports recent developments in IPMC artificial muscle,including improvement methods,modeling,and applications.Different types of IPMCs are described,along with various methods for overcoming some shortcomings,including improvement of Nafion matrix membranes,surface preparation of Nafion membranes,the choice of high-performing electrodes,and new electro-active polymers for enhancing the properties of IPMCs.IPMC models are also reviewed,providing theoretical guidance for studying the performance and applications of IPMCs.Successful applications such as bio-inspired robots,opto-mechatronic systems,and medical engineering are discussed.

Effects of Cu^2＋ Counter Ions on the Actuation Performance of Flexible Ionic Polymer Metal Composite Actuators

The resistance of Ionic Polymer Metal Composite （IPMC） electrodes plays an important role in the actuation performance of IPMC actuators. Owing to crack formation on the surface of platinum electrode, the surface resistance of the electrode increases, which greatly limits its actuating performance. In this paper, we proposed a new method of dynamic self-repair electrodes by ex- changing Cu2＋ into the IPMC basement membrane. IPMC actuators with Cu2＋ were prepared and the actuation performance in the air was subsequently measured. Compared with conventional IPMC actuators containing Li＋ counter ions, those containing Cu2＋ counter ions exhibited 2 times - 3 times larger displacement and 2 times -3 times bigger blocking force. In the morphology observation, we found that many small copper particles scattered in the middle of cracks after several bending cycles, which leads to an obvious decrease in electrode resistance. In the Cyclic Voltammetry （CV） scan measurement, we observed that the oxidation reaction of copper alternates with reduction reaction of copper ions with the change of voltage polarity, which was a dynamic process. Based on these analyses, it is concluded that the presence of Cu2＋ can repair the damaged electrodes and induce lower electrode resistance, thus leading to the performance improvement of actuation.

Ionic polymer-metal composite mechanoelectric transduction:effect of impedance

Ionic polymer–metal composites(IPMCs)are commonly used as soft actuators due to their electromechanical response.However,the reverse phenomenon,i.e.IPMC’s ability to generate charge on application of mechanical strain(mechanoelectric response),is not very well understood.The concept of mechanoelectric transduction and its dependence on complex IPMC architecture comprising of electrode,polymer and composite layer is illustrated with a phenomenological model.The impedance model takes into account the charge transport inside the polymer and layer properties in terms of their impedances.The model lucidly indicates the significance of capacitance in IPMC transduction.The impedance model is used for studying IPMC step and frequency response and the effect of IPMC capacitance on its application as energy harvester.

Wireless actuation and control of ionic polymer-metal composite actuator using a microwave link

The ionic polymer–metal composite(IPMC),a type of electroactive polymer(EAP)actuator,has created a unique opportunity to design robots that mimic the motion of biological systems due to its soft structure and operation at a low voltage.Although this polymer actuator has strong potential for a next-generation artificial muscle actuator,it has been observed by many researchers that supplying actuation voltages in multiple locations is challenging.In robotic applications,a tethered operation is prohibited and the battery weight can be critical for actual implementation.In this research,the remote unit can provide necessary power and control signals to the target mobile robot units actuated by IPMCs.This research addresses a novel approach of using a wireless power link between the IPMC and a remote unit using microstrip patch antennas designed on the electrode surface of the IPMC for transmitting the power.Frequency modulation of the microwave is proposed to selectively actuate a particular portion of the IPMC where the matching patch antenna pattern is located.This approach can be especially useful for long-term operation of small-scale locomotion units and avoids problems caused by complex internal wiring often observed in various types of biologically inspired robots.

Development of an ionic polymer-metal composite stepper motor using a novel actuator model

A novel ionic polymer–metal composite(IPMC)actuated stepper motor was developed in order to demonstrate an innovative design process for complete IPMC systems.The motor was developed by utilizing a novel model for IPMC actuators integrated with the complete mechanical model of the motor.The dynamic,nonlinear IPMC model can accurately predict the displacement and force actuation in air for a large range of input voltages as well as accounting for interactions with mechanical systems and external loads.By integrating this geometrically scalable IPMC model with a mechanical model of the motor mechanism an appropriate size IPMC strip has been chosen to achieve the required motor specifications.The entire integrated system has been simulated and its performance verified.The system has been built and the experimental results validated to show that the motor works as simulated and can indeed achieve continuous 360
rotation,similar to conventional motors.This has proven that the model is an indispensable design tool for integrated IPMC actuators into real systems.This newly developed system has demonstrated the complete design process for smart material actuator systems,representing a large step forward and aiding in the progression of IPMCs towards wide acceptance as replacements for traditional actuators.

Printing ionic polymer metal composite actuators by fused deposition modeling technology

In this work,we printed a Nafion precursor membrane by fused deposition modeling(FDM)rapid prototyping technology and further fabricated IPMCs by electroless plating.The ion-exchange capacity of the Nafion membrane was tested,and the morphology of IPMCs was observed.The electro-mechanical properties of IPMCs under AC voltage inputs were studied,and grasping experiments were performed.The results show that the Nafion membrane after hydrolysis has a good ion-exchange ability and water-holding capacity.SEM observed that the thickness of the IPMC’s electrode layer was about 400 nm,and the platinum layer was tightly combined with the substrate membrane.When using a square wave input of 3.5 V and 0.1 Hz,the maximum current of IPMCs reached 0.30 A,and the displacement and blocking force were 7.57 mm and 10.5 mN,respectively.The new fabrication process ensures the good driving performance of the printed IPMC.And two pieces of IPMCs can capture the irregular objects successfully,indicating the feasibility of printing IPMCs by FDM technology.This paper provides a new and simple method for the fabrication of three-dimensional IPMCs,which can be further applied in flexible grippers and soft robotics.

Modeling Ionic Polymer-Metal Composites with Space-Time Adaptive Multimesh hp-FEM

We are concerned with a model of ionic polymer-metal composite(IPMC)materials that consists of a coupled system of the Poisson and Nernst-Planck equations,discretized by means of the finite element method(FEM).We show that due to the transient character of the problem it is efficient to use adaptive algorithms that are capable of changing the mesh dynamically in time.We also show that due to large qualitative and quantitative differences between the two solution components,it is efficient to approximate them on different meshes using a novel adaptive multimesh hp-FEM.The study is accompanied with numerous computations and comparisons of the adaptive multimesh hp-FEMwith several other adaptive FEM algorithms.

The Development of a Venus Flytrap Inspired Soft Robot Driven by IPMC

In recent years,more and more creatures in nature have become the source of inspiration for people to study bionic soft robots.Many such robots appear in the public’s vision.In this paper,a Venus flytrap robot similar to the biological Venus flytrap in appearance was designed and prepared.It was mainly cast by Polydimethylsiloxane(PDMs)and driven by the flexible material of Ionic Polymer Metal Composites(IPMCs).Combining with ANSYS and related experiments,the appropriate voltage and the size of IPMC were determined.The results showed that the performance of the Venus flytrap robot was the closest to the biological Venus flytrap when the size of IPMC length,width and driving voltage reach to 3 cm,1 cm and 5.5 V,respectively.Moreover,the closing speed and angle reached 8.22°/s and 37°,respectively.Finally,the fly traps also could be opened and closed repeatedly and captured a small ball with a mass of 0.3 g firmly in its middle and tip.

Significantly Enhanced Actuation Performance of IPMC by Surfactant-Assisted Processable MWCNT/Nafion Composite

The performance of Ionic Polymer Metal Composite （IPMC） actuator was significantly enhanced by incorporating surfactant-assisted processable Multi-Walled Carbon Nanotubes （MWCNTs） into a Nation solution. Cationic surfactant Cetyl Trimethyl Ammonium Bromide （CTAB） was employed to disperse MWCNTs in the Nation matriX, forming a homogeneous and stable dispersion ofnanotubes. The processing did not involve any strong acid treatment and thus effectively preserved the excellent electronic properties associated with MWCNT. The as-obtained MWCNT/Nafion-IPMC actuator was tested in terms of conductivity, bulk and surface morphology, blocking force and electric current. It was shown that the blocking force and the current of the new IPMC are 2.4 times and 1.67 times higher compared with a pure Nation-based IPMC. Moreover, the MWCNT/IPMC performance is much better than previously reported Nafion-IPMC doped by acid-treated MWCNT. Such significantly improved performance should be attributed to the improvement of electrical property associated with the addition of MWCNTs without acid treatment.

Modeling of IPMC Cantilever＇s Displacements and Blocking Forces

The motion of an Ionic Polymer Metal Composite （IPMC） cantilever under a periodic voltage control is modeled. In our finite element 3D model, we follow both the free tip displacements and the blocking forces for various thicknesses and elastic constants of the ionomer membrane. It turns out that the maximum displacement of the free tip strongly depends on the value of the Young＇s modulus of the electrodes. Furthermore, the maximum blocking force, Fmax, increases with the thickness of the ionomer membrane. At constant values of Young＇s moduli of the electrodes and ionomer membrane thickness, if the Young＇s modulus of the ionomer membrane varies within the range from 0.2 MPa to 1 GPa, the change of Fmax is less than 10 %. The simulated maximal displacements, blocking forces and electrical currents are compared with the corresponding sets of ex- perimental data, respectively. Qualitative agreement between the simulated and the respective measured data profiles is ob- tained. Furthermore, it is found that the assumption of electrostatic interactions in the cation depleted region of the ionomer membrane has a negligible effect. The advantage of the model consists in its simplicity.

Improving electromechanical output of IPMC by high surface area Pd-Pt electrodes and tailored ionomer membrane thickness

In this study,we attempt to improve the electromechanical performance of ionic polymer–metal composites(IPMCs)by developing high surface area Pd-Pt electrodes and tailoring the ionomer membrane thickness.With proper electroless plating techniques,a high dispersion of palladium particles is achieved deep in the ionomer membrane,thereby increasing notably the interfacial surface area of electrodes.The membrane thickness is increased using 0.5 and 1 mm thick ionomer films.For comparison,IPMCs with the same ionomer membranes,but conventional Pt electrodes,are also prepared and studied.The electromechanical,mechanoelectrical,electrochemical and mechanical properties of different IPMCs are characterized and discussed.Scanning electron microscopy-energy dispersive X-ray(SEM-EDS)is used to investigate the distribution of deposited electrode metals in the cross section of Pd-Pt IPMCs.Our experiments demonstrate that IPMCs assembled with millimeter thick ionomer membranes and newly developed Pd-Pt electrodes are superior in mechanoelectrical transduction,and show significantly higher blocking force compared to conventional type of IPMCs.The blocking forces of more than 0.3 N were measured at 4V DC input,exceeding the force output of typical Nafion®117-based Pt IPMCs more than two orders of magnitude.The newly designed Pd-Pt IPMCs can be useful in more demanding applications,e.g.,in biomimetic underwater robotics,where high stress and drag forces are encountered.

An artificial lateral line system using IPMC sensor arrays

Most fish and aquatic amphibians use the lateral line system,consisting of arrays of hair-like neuromasts,as an important sensory organ for prey/predator detection,communication,and navigation.In this paper a novel bio-inspired artificial lateral line system is proposed for underwater robots and vehicles by exploiting the inherent sensing capability of ionic polymer-metal composites(IPMCs).Analogous to its biological counterpart,the IPMC-based lateral line processes the sensor signals through a neural network.The effectiveness of the proposed lateral line is validated experimentally in the localization of a dipole source(vibrating sphere)underwater.In particular,as a proof of concept,a prototype with body length(BL)of 10 cm,comprising six millimeter-scale IPMC sensors,is constructed and tested.Experimental results have shown that the IPMC-based lateral line can localize the source from 1-2 BLs away,with a maximum localization error of 0.3 cm,when the data for training the neural network are collected from a grid of 2 cm by 2 cm lattices.The effect of the number of sensors on the localization accuracy has also been examined.

Effects of ceramic filler in poly(vinyl chloride)/poly(ethyl methacrylate) based polymer blend electrolytes

Effects of nano-ceramic filler titanium oxide（TiO2） have been investigated on the ionic conductance of polymeric complexes consisting of polyvinyl chloride）（PVC）/poly（ethyl methacrylate）（PEMA）,and lithium perchlorate（LiClO4）.The composite polymer blend electrolytes were prepared by solvent casting technique.The TiO2 nanofillers were homogeneously dispersed in the polymer electrolyte matrix and exhibited excellent interconnection with PVC/PEMA/PC/UCIO4 polymer electrolyte.The addition of TiO2nanofillers improved the ionic conductivity of the polymer electrolyte to some extent when the content of TiO2 is 15 wt%.The addition of TiO2 also enhanced the thermal stability of the electrolyte.The changes in the structural and complex formation properties of the materials are studied by X-ray diffraction（XRD） and Fourier transform infrared spectroscopy（FTIR） techniques.The scanning electron microscope image of nano-composite polymer electrolyte membrane confirms that the TiO2 nanoparticles were distributed uniformly in the polymer matrix.