Self-healing Au/PVDF-HFP composite ionic gel for flexible underwater pressure sensor

Ionic gels can be potentially used in wearable devices owing to their high humidity resistance and non-volatility.However,the applicability of existing ionic gel pressure sensors is limited by their low sensitivity.Therefore,it is very import-ant to develop an ionic gel pressure sensor with high sensitivity and a wide pressure detection range without sacrificing mechan-ical stretchability and self-healing ability.Herein,we report an effective strategy for developing pressure sensors based on ion-ic gel composites consisting of high-molecular-weight polymers,ionic liquids,and Au nanoparticles.The resulting capacitive pressure sensors exhibit high pressure sensitivity,fast response,and excellent self-healing properties.The sensors composed of highly hydrophobic polymers and ionic liquids can be used to track underwater movements,demonstrating broad application prospects in human motion state monitoring and underwater mechanical operations.

Experimental and computational analysis of the structure-activity relationship of ionic gel electrolytes based on bistrifluoromethanesulfonimide salts for supercapacitors

Ionic gel(IG)electrolytes are emerging as promising components for the development of next-generation supercapacitors(SCs),offering benefits in terms of safety,cost-effectiveness,and flexibility.The ionic conductivity,stability,and mechanical properties of the gel electrolyte are relevant factors to be considered and the key to improving the performance of the SC.However,the structure–activity relationship between the internal structure of IGs and their SC properties is not fully understood.In the current study,the intuitive and regular structure–activity relationship between the structure and properties of IGs was revealed via combining computational simulation and experiment.In terms of conductivity,the ionic liquid(IL)([EMIM][TFSI])in the IG has a high self-diffusion coefficient calculated by molecular dynamics simulation(MDS),which is conductive to transfer and then improves the conductivity.The radial distribution function of the MDS shows that the larger the g(r)between the particles in the polymer network,the stronger the interaction.For stability,IGs based on[EMIM][TFSI]and[EOMIM][TFSI]ILs have higher density functional theory calculated binding energy,which is reflected in the excellent thermal stability and excellent capacitor cycle stability.Based on the internal pore size distribution and stress-strain characterization of the gel network([ME3MePy][TFSI]and[BMIM][TFSI]as additives),the highly crosslinked aggregate network significantly reduces the internal mesoporous distribution and plays a leading role in improving the mechanical properties of the network.By using this strategy,it will be possible to design the ideal structure of the IG and achieve excellent performance.

Anti-fatigue ionic gels for long-term multimodal respiratory abnormality monitoring

Wearable electronics integrated with stretchable sensors are considered a promising and non-invasive strategy to monitor respiratory status for health assessment.However,long-term and stable monitoring of respiratory abnormality is still a grand challenge.Here,we report a facile one-step thermal stretching strategy to fabricate an anti-fatigue ionic gel(AIG)sensor with high fatigue threshold(0=1130 J m^(–2)),high stability(>20,000 cycles),high linear sensitivity,and recyclability.A multimodal wearable respiratory monitoring system(WRMS)developed with AIG sensors can continuously measure respiratory abnormality(single-sensor mode)and compliance(multi-sensor mode)by monitoring the movement of the ribcage and abdomen in a long-term manner.For single-sensor mode,the respiratory frequency(Fr),respiratory energy(Er),and inspire/expire time(I/E ratio)can be extracted to evaluate the respiratory status during sitting,sporting,and sleeping.Further,the multi-sensors mode is developed to evaluate patientventilator asynchrony through validated clinical criteria by monitoring the incongruous movement of the chest and abdomen,which shows great potential for both daily home care and clinical applications.

Conductive,Stretchable,and Self-healing Ionic Gel Based on Dynamic Covalent Bonds and Electrostatic Interaction

Integrating multiple functions into one gel that can be widely applied to electronic devices as well as chemical and biomedical engineering remains a big challenge.Here,a multifunctional ionic liquid/dynamic covalent bonds (ionic/DCB) type gel was designed and synthesized via one-pot polymerization.With the assistance of electrostatic interaction provided by the imidazolium cations of IL and the reversible DCB of boronic ester,as-prepared ionic/DCB gel showed good stretchable properties and high ionic conductivity at ambient conditions.In addition,the electrostatic interaction between imidazolium cations and sulfonate anions and the reversible DCB led to enhanced chain mobility and thereby excellent self-healing properties.Particularly,sulfonate anions in ionic/DCB gel could alleviate the migration of electronegative polysulfide and promote the transportation of electropositive lithium ion in lithium-sulfur battery system.Therefore,this work provides a new insight to promote the current research on self-healing gels,hopefully expanding their applications in electronic devices.

Finite element analysis of ionic liquid gel soft actuator

A new type of soft actuator material-ionic liquid gel （ILG）, which consists of HEMA, BMIMBF4, and TiO2, can be transformed into gel state under the irradiation of ultraviolet （UV） light. In this paper, Mooney-Rivlin hyperelastic model of finite element method is proposed for the first time to study the properties of the ILG. It has been proved that the content of TiO2 has a great influence on the properties of the gel, and Young＇s modulus of the gel increases with the increase of its content, despite of reduced tensile deformation. The results in this work show that when the TiO2 content is 1.0 wt%, a large tensile deformation and a strong Young＇s modulus can be obtained to be 325% and 7.8 kPa, respectively. The material parameters of ILG with TiO2 content values of 0.2 wt%, 0.5 wt%, 1.0 wt%, and 1.5 wt% are obtained, respectively, through uniaxial tensile tests, including C10, C01, C20, C11, C02, C30, C21, C12, and C03 elements. In this paper, the large-scaled general finite element software ANSYS is used to simulate and analyze the ILG, which is based on SOLID186 element and nonlinear hyperelastic Mooney-Rivlin model. The finite element simulation analysis based stress-strain curves are almost consistent with the experimental stress-strain curves, and hence the finite element analysis of ILG is feasible and credible. This work presents a new direction for studying the performance of soft actuator for the ILG, and also contributes to the design of soft robot actuator.

Novel Silica Gel Supported Polyether Ionic Liquids: Efficient Catalysts Applied in Transformation of Carbon Dioxide

Three new catalysts based on the silica gel supported polyether ionic liquids(ILs), i.e., [HO-PECH-MIM]ClSi, [H2N-PECH-MIM]Cl-Si, and [HOOC-PECH-MIM]Cl-Si, were prepared, and their chemical structures were characterized by infrared(IR) spectroscopy and nuclear magnetic resonance(NMR) spectroscopy. Thermogravimetric analyzer(TG), X-ray diffractometer(XRD) and scanning electron microscope(SEM) were used to evaluate their thermal stability,crystalline structure and apparent morphology, respectively. Surface areas of the prepared catalysts were calculated by the Brunauer-Emmett-Teller(BET) method. The catalytic reaction for the synthesis of propylene carbonate(PC) using CO_2 and propylene oxide(PO) in the presence of the prepared catalysts was studied. The influences of times of recycling and catalyst structure on catalytic performance were also investigated. The experimental results showed that the silica gel supported polyether ILs catalysts successfully prepared under mild condition could possess the advantages of high activity, excellent thermal stability, good selectivity and easy recycling, while the phase transition of the liquid polyether ILs catalysts was also achieved. When the reaction temperature was 90 °C, the CO_2 pressure was 2.0 MPa and the dosage of the catalyst was 2.5%, [HOOC-PECH-MIM]Cl-Si was found to have the best catalytic performance in the catalytic process, with the conversion rate reaching 100% and the selectivity equating to 98.2%. The conversion rate and selectivity still could reach more than 90% even after the catalyst was reused for 15 times.

New methacrylic imidazolium poly (ionic liquid) gel with super swelling capacity for oil-in-water emulsions

A new polymeric ionic liquid gel was prepared with 1-[(2-methacryloyloxy)ethyl]-3-methylimidazolium bromide(MEMImBr) via radiation-induced polymerization and cross-linking at room temperature.The resultant PMEMImBr gel exhibits high strength and flexibility as well as special swelling behavior in oil-in-water(O/W)emulsions.The swelling behavior of PMEMImBr gel in emulsions is similar to that in water except that the swelling rate in emulsions is slightly smaller than that in water.The organic solvents with higher polarity in the emulsions contribute to the swelling of PMEMImBr gels,and the O/W proportion of emulsion in the swollen gel equals approximately that of original emulsion when the concentration of organic solvent is lower than 0.2 g/g.

Immobilization of Functionalized Ionic Liquid on Sol-Gel Derived Silica for Efficient Removal of H_2S

An innovative approach to H2 S capture has been developed using several metal-based ionic liquids([Bmim]Cl·CuCl_2, [Bmim]Cl·FeCl_3, [Bmim]Cl·ZnCl_2, [Bmim]Br·CuCl_2, and [Bmim]Br·FeCl_3) immobilized on the sol-gel derived silica, which is superior to purely viscous ionic liquid with a crucial limit of high temperature, low mass transfer rate,and mass loss. The adsorbents were characterized by the Fourier transform infrared spectrometer, transmission electron microscope, N_2 adsorption/desorption, X-ray photoelectron spectroscopy, and thermal analysis techniques. The effects of the metal and halogen in IL, the loading amount of IL, and the adsorption temperature were studied by dynamic adsorption experiments at a gas flow rate of 100 mL/min. The H2 S adsorption results have showed that the optimal adsorbent and adsorption temperature are 5% [Bmim]Cl·CuCl_2/silica gel and 20—50 ℃, respectively. H_2 S can be captured and oxidized to elemental sulfur, and [Bmim]Cl·CuCl_2/silica gel can be readily regenerated by air. The excellent efficiency of H2 S removal may be attributed to the formation of nano-scaled and high-concentration [Bmim]Cl·CuCl_2 confined in silica gel, indicating that the immobilization of [Bmim]Cl·CuCl_2 on the sol-gel derived silica can be used for H2 S removal promisingly.

Silica Gel Supported Hydrophobic Ionic Liquid for Selective Extraction and Determination of Coumarin

In this study, a modified silica gel surface with a hydrophobic ionic liquid (SG-1,10-PhenanNTf2) was used as an adsorbent for a selective extraction of coumarin prior to its determination by use of high performance liquid chromatography. Results demonstrated that SG-1,10-PhenanNTf2 phase had a good adsorption capacity up to 85.29 mg?g?1, high selectivity, good site accessibility and fast binding kinetics toward coumarin. The adsorption capacity for coumarin was improved by 62.33% with the SG-1,10-PhenanNTf2 phase as compared to activated silica gel. Adsorption isotherm data displayed that the adsorption process was mainly monolayer on a homogeneous adsorbent surface, confirming the validity of Langmuir adsorption isotherm model. The adsorption of coumarin on the SG-1,10-PhenanNTf2 phase was accomplished after only 60 min contact time. Results of kinetic models showed that the adsorption of coumarin on the SG-1,10-PhenanNTf2 phase obeyed a pseudo second-order kinetic model. Finally, the efficiency of this methodology was confirmed by applying it to real water samples.

Preparation and Ionic Conductivity of Ultrafine Li_(2+x)RE_xSi_(1-x)O_3 by Sol-Gel Method

Li 2+ x RE x Si 1- x O 3(RE=Pr, Nd, Sm, Gd; x =0～0 15) samples were prepared by the sol gel method. DTA TG, XRD, TEM and A C impedance techniques were used to investigate the structure, shape, and ionic conductivity of these samples. The results show that the range of solid solution formation is in 0< x ≤0 09, in which the conductivity of these samples raises with the increasing amount of RE 2O 3 (RE=Pr, Nd, Sm, Gd) added, and the diameter of the powders is about 100 nm. Compared with the conventional solid state reaction, the sol gel method needs low temperature and presents high ionic conductivity.

Electric Conductivity of Fluorinated Oligomer Gel Electrolyte Including Ionic Liquid and Performance of Dye Sensitized Solar Cell

Fluorinated oligomer gel is suitable to the electrolyte of dye sensitized solar cell. This article studied mainly in the scope of electric conductivity, including ionic liquid in the electrolyte. It was found that the ratio of mixing with dimetyl sulfoxide and the concentration of LiI affect the conductivity. The behavior is different depending on the type of ionic liquid. Although the mixing ionic liquid enhances the conductivity, the short circuit current density of assembled solar cell with it was suppressed so much.

离子液体凝胶催化剂在合成乙酸正龙脑酯中的应用

乙酸正龙脑酯作为医药中间体,具有广泛用途。无论是传统工艺的酸性催化剂,还是离子液体催化剂都存在催化剂与反应物有效分离困难、不易循环使用的缺点。将具备温敏性的离子液体凝胶作为乙酸正龙脑酯的新型催化剂,可突破离子液体催化酯化反应工业化的技术瓶颈。本工作以离子液体1-丁基-3-甲基咪唑硫酸氢盐、聚乙烯醇、单宁酸为原料,基于超分子组装原理,制备了温敏性离子液体凝胶催化剂。采用流变仪、热重分析仪、傅里叶变换红外光谱仪、核磁共振波谱仪对离子液体凝胶进行表征。结果显示,PVA-Ta-[BMIM]HSO4离子液体凝胶中存在羧酸酯键和氢键,是由咪唑环和苯环的π-π堆积作用构成的混合双网络聚合物,具有较高的机械强度和韧性。以乙酸正龙脑酯为反应模型,考察了离子液体凝胶催化剂的活性,通过单因素实验法优化了离子液体凝胶催化剂合成乙酸正龙脑脂的反应条件,得到反应温度为90℃,反应时间为6 h,α-蒎烯与冰醋酸的物质的量比为1∶1。实验结果表明,该催化剂对温度产生可逆相变响应,高温时反应体系为均相,保证了催化效率,反应结束后降温凝固成为凝胶并析出。离子液体凝胶的催化活性与酸性离子液体的活性差别不大,重复使用五次后,α-蒎烯转化率保持在75%以上,乙酸正龙脑酯的选择性在8.5%以上。

用于应变传感器的自愈合抗冻离子水凝胶

近年来,导电水凝胶在电子驱动器、医疗监测传感器及可穿戴设备等领域的应用备受关注。然而,多数凝胶机械强度低、寿命短、抗冻性能差,从而导致低温下无法使用。为了解决该问题,以聚乙烯醇、离子液体1-丁基-3-甲基咪唑四氟硼酸盐和植酸为原料,在水与二甲基亚砜(DMSO)二元溶液中借助多重氢键及离子基团间的静电作用实现了超分子自组装,制备出一种可用于应变传感的自愈合、耐低温多功能离子水凝胶。研究发现在凝胶中引入DMSO,凝胶表现出优异的抗冻能力;同时,调节DMSO的含量可优化凝胶的强度和韧性,当DMSO体积分数为40%时,最大拉伸强度和断裂伸长率分别可达4.43 MPa和869.1%。该离子水凝胶在低温应变传感器、智能可穿戴响应元件等领域展现出较好的应用潜力。

前沿科研成果融入高分子物理实验教学——以抗冻性导电离子凝胶的制备与性能研究为例

高分子物理是高分子化学专业和材料类专业的一门专业必修课程,在高分子材料开发和应用中极为重要。以科研促进教学是提高高校教学质量的重要途径。本文以离子液体作为多功能组分(分散相、抗冻剂、增塑剂和导电剂),通过光引发聚合含氟酯类单体(2,2,3,4,4,4-六氟丙烯酸丁酯)和丙烯酸单体制备具有抗冻性的离子凝胶,进一步考察离子液体的含量对离子凝胶的力学性能、抗冻性和离子电导率的影响。该实验可以培养学生的实验综合能力和深入理解聚合物结构对性能的影响关系。通过该实验教学改革,促进学生掌握原理和实验技能,激发学习热情,培养科学思维和科研创新能力。

离子强度对乳清蛋白-透明质酸乳液凝胶结构和流变性能的影响

文章旨在探究不同浓度Na^(+)、Ca^(2+)对于乳清分离蛋白-透明质酸乳液凝胶结构和流变性能的影响。制备乳清分离蛋白-透明质酸复合物溶液,向其中分别加入不同浓度(25、50、100、200 mmol/L)的NaCl、CaCl2制成乳液凝胶;利用粒径电位、内源荧光测定溶液性质。通过测定乳液凝胶质构、持水性、流变性,激光共聚焦显微镜观察乳液凝胶网络结构。结果表明,加入离子使乳液凝胶具有更好的质构、流变性能、持水性和更均匀更紧凑的网络结构,提高了乳液凝胶稳定性。Na^(+)浓度为50 mmol/L时,溶液电位绝对值最高,凝胶质构、流变性能、持水性较好,此时乳液凝胶有良好的网络结构。Ca^(2+)浓度为50 mmol/L时,乳液凝胶质构性能最好、保水能力最强,有良好的乳液凝胶网络结构。为乳清蛋白基乳液凝胶的凝胶特性调控提供了技术支撑。

高电导率抗冻离子凝胶的制备及性能研究

近年来,可穿戴设备在人体运动、身体体征以及体液检测等方面得到广泛应用。离子凝胶依靠其优异的离子导电性、热稳定性和电化学性能,广泛应用于柔性传感器,包括传感单元和柔性电极。大多数可穿戴传感器对低温条件的适应度不高,这阻碍了其在不同环境下的使用。鉴于此,本工作提出了一种高电导率抗冻离子凝胶,将丙烯酸(AA)、羧甲基纤维素钠(CMC)、丙烯酰胺(AAm)三种物质以AA与CMC,AA与AAm,AA、CMC和AAm三种组合相互形成共聚网络,并加入LiCl导电物质来制备一种在低温下依旧能保持良好电化学性能的离子凝胶。在三种类型的离子凝胶中,AA-CMC离子凝胶具有最高的电导率和对金属类器件表面最好的粘附性,对铁片的最大粘附力可达51.39 kPa,同时还具有优良的保湿抗冻功能(在25℃下7 d内失水率仅为4%以及-76℃的凝固点)和207.10%的断裂生长率。AA-CMC离子凝胶具有较好的导电性能(电导率最大为0.617 S/m)及柔软特性,可以组装成可穿戴柔性压力传感器;具有稳定的电化学性能且在长期在低温下也能保持自身的导电性能(-18℃冷冻3周电导率保持约原有的86.3%)。本工作所制备AA-CMC的离子凝胶将有望扩展其在柔性电子设备中的应用范围与使用前景。

高强度离子导电凝胶研究进展

近年来,柔性可穿戴电子产品在人机交互、传感器等方面应用越来越广泛。离子导电凝胶具有高导电性、生物相容性、自愈合、良好的机械性能以及对可见光透明度高等特点,力学性能对离子导电凝胶的应用影响较大,通过添加纳米填料、无机盐和有机盐、聚电解质可以提升离子导电凝胶的力学性能。综述了纳米复合离子导电凝胶、盐离子导电凝胶、聚电解质离子导电凝胶的研究进展,对离子导电凝胶在传感器、柔性皮肤、生物医药等领域中的应用以及面临的困难和挑战进行了探讨,并展望了其未来发展方向。

光固化3D打印可聚合低共熔导电凝胶

离子凝胶对于柔性电子设备的发展具有重要意义,然而离子液体价格昂贵、有毒易造成环境污染。使用氯化胆碱(CHCL)、丙烯酸羟乙酯(HEA)、丙烯酰胺(AAm)制备了可聚合低共熔溶剂(PDES)替代传统离子液体,利用数字光处理(DLP)3D打印的成型方法,通过紫外光引发自由基聚合制备了P(HEA-co-AAm)-CHCL低共熔凝胶。通过傅里叶变换红外光谱、差示扫描量热分析证明了PDES的成功制备。对P(HEA-co-AAm)-CHCL的导电性能、力学性能、光学性能、传感性能进行了测试分析。结果表明,当CHCL和可聚合单体的物质的量之比为1∶3.5时凝胶的导电性能最好,离子电导率可达1.1×10-2 S/m。然后,固定CHCL和可聚合单体的物质的量之比为1∶3.5,改变HEA和AAm的物质的量之比制备了5种P(HEA-co-AAm)-CHCL,结合导电性能和力学性能测试结果发现,当HEA与AAm的物质的量之比为2.5∶1时,其拉伸强度、断裂伸长率分别为2.81MPa,1200%;具有优异的光学透明性,可见光透过率能够达到90%;应变系数为0.74;此外,具有优异的传感性能、循环稳定性等。

凝胶树脂负载离子液体固体酸催化酯化反应性能

针对酯化反应传统浓硫酸催化剂易腐蚀和产生大量含酸废水难题,通过一锅法将离子液体负载于凝胶树脂上,制备了绿色高效的凝胶树脂负载离子液体固体酸(SA-ILs)催化剂。研究表明:凝胶树脂载体具有强吸水结构,离子液体通过化学键共价负载在凝胶树脂载体上,SA-ILs催化剂具有优异的酸性和良好的结构稳定性。当离子液体为最佳载量11%时,合成的SA-ILs催化剂酸密度达3.25 mmol·g^(-1),对乙酸和乙醇之间的酯化反应具有良好的催化性能,乙酸乙酯的收率可达81%,并且循环复用5次使用后催化性能没有明显下降,而其较低的活化能是催化酯化反应更易进行的关键。

载铜纳米粒鼻用原位凝胶体外释放度研究

为研究载铜纳米粒鼻用原位凝胶(TETA-Cu-NPs-gel)中三乙烯四胺铜(TETA-Cu)的体外释放规律,通过透析法研究TETA-Cu的体外释放度,以0.1 mol/mL磷酸盐缓冲液(PBS,pH=7.4)为释放介质,并用Origin软件对释药数据进行模型拟合。采用高效液相色谱法检测TETA-Cu在溶出介质中的释放水平,以Swell Chromplus^(TM)C_(18)(4.6 mm×150 mm,5μm)为色谱柱,流动相A为pH=3.0磷酸盐缓冲液,流动相B为甲醇(A∶B=90∶10),流速1.0 mL/min,检测波长为260 nm。结果表明,TETA-Cu在0.05~1 mg/mL范围内线性关系良好,高、中、低三个浓度的回收率在99.9%~101.0%,RSD均小于2%;与TETA-Cu溶液相比,TETA-Cu-NPs-gel释药速率缓慢,符合一级释药动力学方程。可见,本文研究所建立的TETA-Cu-NPs-gel体外释放度测定方法准确、简便可行。TETA-Cu-NPs-gel具有缓释的作用。