复合钒钛酸掺杂聚苯胺湿敏特性的正交实验

采用sol-gel法制备钒钛酸并掺杂聚苯胺制备湿敏元件,通过正交实验的方法,探索出较优越的实验条件及组装最佳的湿敏元件。测试了元件在不同湿度下的电阻,结果表明:当钒钛酸掺杂聚苯胺在浸渍2次,掺杂45min,氧化剂用量为40mL时具有灵敏度高、湿敏性好的特点。     

高温金属氧化物陶瓷湿敏传感器研究

本文论述了采用湿法合成可在高温下应用的改性羟基磷灰石感湿粉料工艺有关性能，系统研究了应用上述改性ＨＡＰ感湿粉料，采用厚膜丝网印工艺技术制成的湿敏元件和传感器的各项湿敏性能，探讨了有关工艺参数对元件性能的影响，通过中国建筑科学研究院空气调节研究所近两年的系统测试，首次给出了高温下的湿度－电阻特性曲线。     

Na1＋xZr2P3—xSixO12系统的湿敏元件

研究了Na_(1 x)Zr_2P_(3-x)Si_xO_(12)(x=0～1)系统的湿敏元件的结构组成和性能,发现在0〈x〈1区域形成连续型固溶体,在O.8〈x〈0.85区域有较好的感湿特性.对部分区域内湿敏元件的主要特性进行了半理论计算,计算结果与实测结果相近.     

氧化石墨烯/钒钛酸复合材料的制备及湿敏性能研究

通过Hummers法制备氧化石墨后进行超声分散,得到分散均匀的氧化石墨烯(GO)分散液,物理复合滴涂制备氧化石墨烯/钒钛酸薄膜并对其感湿性能进行了研究,并通过交流与直流方法对其感湿机理进行了深入探究。结果表明:氧化石墨烯/钒钛酸复合膜的湿敏性能优于氧化石墨烯和钒钛酸单层膜,该湿敏薄膜的湿滞为8.3%RH,灵敏度变化2个数量级,响应时间为8 s,还原时间为10 s,曲线线性度良好。材料在低湿阶段主要表现为电子导电,中高湿阶段为电子导电和离子导电同时存在,高湿阶段主要表现为离子导电。     

高分子材料电阻型湿敏元件光辐射预老化处理的实验与研究

采用了光辐射预老化处理高分子材料电阻型湿敏元件,并通过测量预处理湿敏元件前后的电阻值和长期跟踪测试来研究其性能变化。结果表明,被适当的光辐射如氦氖激光预老化处理湿敏元件的感湿特征量的长期稳定性变好了,其它性能变化不大。     

高分子材料电阻型湿敏元件的交流电激励预老化处理的实验与研究

采用了交流电激励老化法预处理高分子材料电阻型湿敏元件,并通过测量湿敏元件预处理前后的电阻值和长期跟踪测试来研究其性能变化。结果表明,被适当的交流电激励老化预处理的湿敏元件的感湿特征量的线性和长期稳定性变好了,其它性能变化不大。     

HDPE粉料表面光接枝乙烯基吡咯烷酮及其性能的研究

通过紫外线(UV)引发乙烯基吡咯烷酮(NVP),在高密度聚乙烯(HDPE)粉料表面进行接枝反应,制得了NVP接枝HDPE材料,研究了反应时间对接枝率、接枝物亲水性能及其粘接强度的影响.实验结果表明:紫外线能有效引发NVP在HDPE粉料表面的接枝聚合,随辐照时间延长,接枝率升高;接枝改性后HDPE与水的接触角下降,亲水性增强;HDPE/钢材的粘接强度大幅度提高,可高于HDPE材料的本体强度.     

添加剂对ZrO_2-MgO系湿敏陶瓷湿阻性能的影响

本文研究了ZrO_2-MgO系湿敏陶瓷Zr/Mg比及添加剂对其湿阻性能的影响,摸索了有关配方和工艺。实验结果表明,提高Zr/Mg比,并引入某些M_2O_3(M为三价金属元素)外加剂对湿阻性能有利,但低温下元件的阻值仍较高。进一步添加外加剂如Li_2CO_3,可使湿阻性能得到改善。     

纳米湿敏陶瓷α-Fe2O-Al2O3-K2O的制备与性能

采用溶胶-凝胶法新工艺制备了不同配比的纳米级α-Fe2O3-Al2O3-K2O复合氧化物湿敏陶瓷.XRD、BET比表面吸附、Archimede排水法等手段对系列纳米陶瓷物相及微结构进行了分析表征.湿敏特性测试结果表明:调控各组分摩尔配比为r(Fe:Al:K)=90:5:5,可获得全湿区阻-湿特性线性关系良好、感湿灵敏度较高、湿滞小、使用温度范围宽、响应速度较快、性能一致性优的湿敏元件.提出组份间界面作用模型,并初步探讨了影响材料阻-湿特性及湿滞的内在因素.     

纳米湿敏陶瓷α-Fe_2O_3-Al_2O_3-K_2O的制备与性能

采用溶胶—凝胶法新工艺制备了不同配比的纳米级α -Fe2 O3 -Al2 O3 -K2 O复合氧化物湿敏陶瓷。XRD、BET比表面吸附、Archimede排水法等手段对系列纳米陶瓷物相及微结构进行了分析表征。湿敏特性测试结果表明 :调控各组分摩尔配比为r(Fe∶Al∶K) =90∶5∶5,可获得全湿区阻—湿特性线性关系良好、感湿灵敏度较高、湿滞小、使用温度范围宽、响应速度较快、性能一致性优的湿敏元件。提出组份间界面作用模型 ,并初步探讨了影响材料阻—湿特性及湿滞的内在因素     

Effect of BaTiO3 on the sensing properties of PVDF composite-based capacitive humidity sensors

Capacitive humidity sensors consisting of materials such as polymers, ceramics, and piezoelectrics are widely used to monitor relative humidity levels. The effect of barium titanate (BaTiO₃) nanoparticles on the humidity sensing properties, dielectric response, thermal stability, and hydrophilicity of the polyvinylidene fluoride (PVDF)-BaTiO₃ composite films is investigated. Hydrophilicity and surface morphology of the PVDF-BaTiO₃ composite films are modified for the development of a good humidity sensor. The nanocomposite solutions are prepared by mixing an optimized concentration (2.5 wt%) of PVDF with different concentrations (0.5, 1, and 2 wt%) of BaTiO₃ nanoparticles. X-ray diffraction, thermogravimetric analysis, field emission scanning electron microscopy, and contact angle measurements are used to characterize the structure, morphology, thermal stability, and hydrophilicity of the spin-coated sensing films. The dielectric study of PVDF-BaTiO₃ composite film shows that as the concentration of BaTiO₃ particles increase, the dielectric constant of the composite films increases as well. PVDF-BaTiO₃ (2.5 wt%-1 wt%) based capacitive sensors show stable capacitive response and low hysteresis as compared to the other concentrations of the PVDF-BaTiO₃ composites. The maximum hysteresis of the capacitive PVDF-BaTiO₃ (2.5 wt%- 1 wt%) humidity sensor is found to be ~2.5%. The response and recovery times of the PVDF-BaTiO₃ (2.5 wt%-1 wt%) based capacitive sensors are determined as 40 s and 25 s, respectively, which are significantly lower than those reported for the other PVDF composite based sensors.     

UV‐Printable and Flexible Humidity Sensors Based on Conducting/Insulating Semi‐Interpenetrated Polymer Networks

Humidity sensors are of great interest in many fields because humidity plays a crucial role in several processes. Nevertheless, their application is often limited by the expensive fabrication and the stiffness of the substrates usually employed. In this work, novel UV‐curable and flexible humidity sensors based on semi‐interpenetrated polymer networks are fabricated. They can be prepared either as self‐standing sensors or applied on different bendable substrates. The fabrication consists of a simultaneous UV‐curing of an insulating network (acrylic or epoxy) and photopolymerization of conducting polypyrrole (PPy). The detection mechanism involves proton transfer on the PPy chains that can be macroscopically observed by electrical impedance variations. These devices show promising humidity‐sensing properties from 20 to 97% of relative humidity with a maximum response of about 180%. The dynamic sensing investigation proves that the recovery process can be tailored playing on the glass transition temperature and wettability of the films. The remarkable sensing capabilities of these sensors make them a valid alternative in many applications where printability and flexibility are required along with simple fabrication method consisting of one‐step synthesis.     

Synthesis and humidity sensitive properties of pyrrole‐based polyelectrolytes

Pyrrole (Py)‐based polyelectrolytes (Py‐PE): P(Py‐COOLi), P(Py‐COONa), and P(Py‐COOK) was synthesized, characterized, and used to prepare thin film resistive humidity sensors. Their humidity sensitive properties have been investigated, and sensing mechanism was presented. The Py‐PE contains PPy as backbone and the side chain bearing carboxylic salt group, which made its sensor exhibited a very wide humidity sensing range of 0–97% relative humidity (RH), high conductivity even at very low humidity, and both ionic and electronic conduction contributed to its conductivity. Among all the Py‐PE, P(Py‐COOK) showed high sensitivity, with the impedance changing of about three orders of magnitude (10³–10⁶ Ω) from 97 to 0% RH, whereas P(Py‐COONa) showed quick response for both absorption (12.5 s) and desorption (15.2 s). Py‐PE prepared is promising for preparation of thin film resistive humidity sensors capable of detecting low humidity. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

无铅铜基钙钛矿Cs2CuBr4的湿度传感性能

铅卤钙钛矿因其优异的光电性能引起了人们的极大关注,但由于其内在的不稳定性以及铅的毒性问题,限制了其实际应用。本文制得一种性能较稳定的无铅铜基钙钛矿Cs₂CuBr₄,利用其对湿度较为敏感的特性,创制了基于Cs₂CuBr₄敏感膜的石英晶体微天平（quartz crystal microbalance, QCM）湿度传感器。结果表明,当钙钛矿溶液的浓度小于0.4μg/μL时,敏感膜在11%~84%相对湿度下具有良好的湿度传感性能。其中最优浓度为0.3μg/μL（QCM-3）、薄膜质量398.95ng时,传感器具有高灵敏度（37.65Hz/% RH）,优异的对数线性关系（R²=0.9948）和快速的响应/恢复时间（5s/1s）。由此可见,无铅铜基钙钛矿Cs₂CuBr₄在湿度传感领域具有良好的应用前景。     

Wide range humidity sensors printed on biocomposite films of cellulose nanofibril and poly(ethylene glycol)

Cellulose nanofibril (CNF) films were prepared from side streams generated by the sugarcane industry, that is, bagasse. Two fractionation processes were utilized for comparison purposes: (1) soda and (2) hot water and soda pretreatments. 2,2,6,6-Tetramethylpiperidinyl-1-oxyl-mediated oxidation was applied to facilitate the nanofibrillation of the bagasse fibers. Poly(ethylene glycol) (PEG) was chosen as plasticizer to improve the ductility of CNF films. The neat CNF and biocomposite films (CNF and 40% PEG) were used for fabrication of self-standing humidity sensors. CNF-based humidity sensors exhibited high change of impedance, within four orders of magnitude, in response to relative humidity (RH) from 20 to 90%. The use of plasticizer had an impact on sensor kinetics. While the biocomposite film sensors showed slightly longer response time, the recovery time of these plasticized sensors was two times shorter in comparison to sensors without PEG. This study demonstrated that agroindustrial side streams can form the basis for high-end applications such as humidity sensors, with potential for, for example, packaging and wound dressing applications. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47920.     

Functionalized multi‐wall carbon nanotubes/silicone rubber composite as capacitive humidity sensor

Functionalized multi‐wall carbon nanotubes (MWCNTs) treated by mixed acids have been used to develop a capacitive humidity sensor based on MWCNTs/silicone rubber (SR) composite film. The MWCNTs/SR composites were prepared through conventional solution processed method. The micrographs of MWCNTs/SR composites were observed by transmission electron microscopy (TEM) and scanning electron microscope. The FT‐IR spectra demonstrated the successfully grafting of ? OH groups on the treated MWCNTs. The sensing properties of the composite at different relative humidity (RH) and frequency were characterized and linear sensing responses of the MWCNTs/SR composites to RH were observed. The treated MWCNTs/SR composite film (Tr‐film) had higher sensitivity than that of the untreated MWCNTs/SR composite film (Un‐film). Experimental data indicate that the Tr‐film exhibits an excellent long‐term stability, small hysteresis, and fine reproducibility. The response and recovery time of the Tr‐film were 30 and 27 s, respectively. Thereby, such Tr‐film had potential applications as humidity sensors. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40342.     

Polymer latex containing carboxylic acid functional groups. II. Humidity‐sensitive properties of rigid films made from MMA and AA

The polymer latexes of poly(MMA‐AA) were synthesized using two techniques: soapless seeded emulsion polymerization, and soapless emulsion copolymerization. Then a series of rigid polymer films containing a COOH group were prepared from the synthesized latex. The humidity‐sensitive properties of the polymer films were investigated. Our studies confirmed that there exists both an optimum ratio of hydrophilic to hydrophobic monomers and initial structure of the latex particle that provides the humidity‐sensitive polymer film with excellent water resistivity and sensitivity to humidity. In addition, little hysteresis and quick response were observed. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 3121–3129, 1999     

基于硝化纳米纤维素/琼脂的高灵敏度湿度传感器

湿敏材料是决定湿度传感器性能的关键,本研究将具有特殊化学结构的纤维素和琼脂这两种生物质材料有机结合起来,制备具有不同湿度敏感性的硝化纳米纤维素/琼脂（nitrocellulose nanocrystals/Agar,NCNCs/Agar）复合敏感膜材料,基于石英晶体微天平（quartz crystal microbalance,QCM）制备出具有高灵敏度的湿度传感器。结果表明,NCNCs/Agar复合敏感膜修饰的QCM湿度传感器的灵敏度和频率响应值较单一材料敏感膜修饰的QCM均有较明显的提高。经过优化测试,得到NCNCs与琼脂的最佳质量比为1∶25,涂覆2.049μg敏感材料的QCM传感器（QCM-b）性能最优异。在相对湿度（RH）11%~84%下,QCM-b具有良好的线性（R²=0.9933）,灵敏度为32.54Hz/%RH。在RH 11%~97%下,QCM-b响应值可达到-5820Hz,具有优异的对数拟合系数（R²=0.9994）,恢复时间短（5s）,并且具有良好的重现性和长期稳定性,显示出在湿度探测领域的良好应用前景。     

Preparation and characterization of isotactic polypropylene/high‐density polyethylene/carbon black conductive films with strain‐sensing behavior

Novel conductive films with a unique strain (ε)‐sensing behavior and based on a blend of isotactic polypropylene (iPP), high‐density polyethylene (HDPE), and carbon black (CB) were fabricated by an extrusion casting method. The morphology and ε‐sensing behavior of the films were investigated. Scanning electron microscope images showed that the oriented lamellae with a growing direction perpendicular to the extrusion direction were obtained in the HDPE phase and were accompanied by a cocontinuous structure of the iPP phase and HDPE/CB phase. The conductive percolation threshold (m_c) and resistivity–ε behavior of the thin films are affected by the drawing ratio during the process of film preparation. The m_c and electrical resistance of the iPP/HDPE/CB composite films increased with the drawing ratio. The gauge factor of the films within the elastic region decreased with increasing drawing ratio. Furthermore, the result of iPP/(HDPE/CB) 40/60 with a high drawing ratio shows that a reversible conductivity was obtained during the cyclic tensile testing (ε = 10%), but an irreversible conductivity makes the film fail during use at the applied ε values of up to 15%. This makes them good piezoresistive candidates for ε‐sensing materials. Moreover, a simple structural model was proposed to describe the reversible and irreversible phenomena in the electrical resistance behavior of the iPP/HDPE/CB films under tensile loading. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40686.     

Flexible Humidity and Pressure Sensors Realized by Molding and Inkjet Printing Processes with Sandwich Structure

Flexible and wearable devices are important parts toward the realization of artificial intelligence and have an irreplaceable advantage over traditional rigid sensors. In this work, a film with double surface structure is prepared by using sandpaper and the leather with a rhombic structure as a mold, thereby obtaining a sandwich structure resistive type pressure sensor, which has high sensitivity (77.78 kPa^?1, 24 Pa minimum detection) and wide detection range (0.024–230 kPa). The sensors have fast response time (30 ms) and high reliability over 5000 repetitive cycles. The humidity sensor is printed on the top layer of the sensor by using screen printing and inkjet printing technique, and the sandwich structure humidity and pressure sensor is obtained. The humidity sensors show the sensitivities of 0.137/%, 1.57/%, and 11.145/% in the relative humidity range from 25 to 55%, 55 to 70%, and 70 to 80%, respectively. Such sensors not only have excellent capabilities in pressure and humidity detection, but also avoid the complex process of multiple single‐function devices stacked on each other. The applications of sensors in monitoring artery pulse waves, detecting spatial pressure distribution, and sweat is demonstrated.