织物表面微滴喷射打印沉积过程试验研究

在织物表面微滴喷射打印沉积成形微细导电线路中,明确微滴在织物表面碰撞和渗透过程是成形高质量导电线路的前提。采用试验研究的方法,在喷射系统可控喷射条件下,对微滴与织物表面的碰撞、铺展及渗透过程进行图像采集及动态过程研究。结果表明：微滴在织物基板表面的碰撞过程与固体基板类似,几乎未发生渗透现象;由于毛细压差的作用,不同织物在不同时间段内的渗透速率急剧增大,出现快速芯吸现象,且织物经纬密度越小,芯吸效果越明显;微滴在织物表面的扩散形状由织物的组织结构决定,扩散面积与织物润湿性有关,随润湿性的减弱而减小。     

微喷印原电池置换成型织物基柔性导电线路的影响因素研究

针对目前智能纺织品中柔性导电线路制备工艺复杂、成本高、与纺织品融合度低等问题,提出了微喷印原电池置换成型织物基导电线路的制备方法。利用搭建的压电式微滴喷射系统,对沉积过程中硝酸银和抗坏血酸反应物浓度、反应物质量及原电池阳极基板的选择对成型导线微观形貌及方阻的影响进行研究。结果表明:在稳定喷射条件下,通过微喷印原电池置换沉积法可制备织物基导电线路;当硝酸银溶液、抗坏血酸溶液质量浓度分别为0.5 g/mL和0.3 g/mL、硝酸银打印层数为4层、织物与抗坏血酸溶液质量比为1∶2时,成型银导线方阻为 0.047 8 Ω/□, 标准偏差为0.009 138 Ω/□;当基板为铜时,在织物基底表面形成了均匀且致密的银层,银颗粒粒径较大,此时测得银导线方阻均值及标准偏差较小。     

织物表面导电线路喷射打印中微滴关键参数的视觉测量

针对织物表面打印导电线路中微滴的几何尺寸、速度等参数测量过程自动化程度低的问题,将视觉测量与微滴喷射技术相结合。利用高速相机对微滴喷射过程进行拍摄得到连续微滴图像。基于像素的阈值选取方法对微滴图像进行分割,得到微滴的二值图像,采用阶梯型边缘检测算法提取液滴边缘轮廓,获得单个微滴的面积、直径参数,根据面积和直径的关系计算出单个微滴的圆度参数,根据2帧微滴图像间的位移量计算出微滴的瞬时速度。实验结果表明:采用视觉测量法测得到的结果精度可达像素级,整个测量过程耗时短,可实现实时测量,为后续织物表面导电线路的精确成形提供了必要监测手段。     

微滴喷射化学沉积工艺条件对成形银导线的影响

为制备具有良好导电特性的柔性线路,研究了织物表面微滴喷射打印化学沉积的工艺条件变化对成形导电线路性能的影响。利用开发的气动式双喷头微滴按需喷射系统,通过改变反应溶液中硝酸银和抗坏血酸的用量、分散剂聚乙烯吡络烷酮(PVP)的浓度及反应体系的pH值,在系统稳定喷射条件下打印导电线路,对不同条件下成形导线的微观形貌进行观察,并测试成形导线的方阻。结果表明:在稳定喷射条件下,当硝酸银和抗坏血酸用量分别为50%和30%(质量体积比)时,反应生成的银导线平均方阻为2.92 Ω/□,标准差为0.46 Ω/□;分散剂PVP在银导线反应过程中具有控制银微粒大小和改善粒子间团聚的作用,且当分散剂PVP添加量为6%时,银颗粒成“米粒”状,颗粒间连接成网状结构;不同pH值条件下反应体系的反应情况不同,当反应体系的pH值为2~3时,反应生成银粒子较多,且颗粒形状规则统一。     

织物表面导电线路成形方法的研究进展

本文从当前织物表面导电线路的成形方法、应用等方面着手,对其现有的成形方法进行综述,指出各成形方法存在的问题,如工艺复杂、柔韧性差、成本高等,并提出了一种新型织物表面导电线路成形方法——微滴喷射自由成形导电线路技术。此外,还阐述了导电线路在智能纺织品、信息传输、医疗保健等领域的应用,最后对不同的成形方法进行了总结,并指出织物导电线路应朝着智能化、集成化、舒适性、成本低等方向发展。     

基于Faster R-CNN的织物表面打印导电线路中微滴目标检测

针对织物表面打印导电线路中传统的微滴目标检测通用性及智能化程度低的问题，使用深度学习模型实现了微滴形态的实时检测。通过对训练图片进行预处理，使用Labelimg工具标记不同形态的微滴灰度图像目标区域，生成相应的数据信息库，为后续的训练和测试提供数据集。利用深度学习目标检测模型训练标记好的数据集，得到最优检测模型。实验结果表明：相比于传统目标检测方法，深度学习检测模型对不同形态的微滴具有很好的适用性；相比于其他深度学习模型，Faster R-CNN模型的精度更高，对正常微滴和不良液滴检测的平均精度均值为84.89%。该研究为后续织物表面导电线路的精确成形提供了参考。     

等离子体处理对织物表面溅射铜膜性能的影响

利用直流磁控溅射法,在涤纶织物表面沉积纳米铜薄膜,研究氧、氩等离子体处理前后涤纶基材表面沉积铜膜的形貌、导电性能和润湿性能的变化.以扫描电子显微镜(SEM)和原子力显微镜(AFM)观察低温等离子体处理前后纤维表面的粗糙度和纳米铜颗粒大小变化,并对表面沉积纳米铜织物导电性能、润湿性能进行测试,结果表明,氧等离子体处理对涤纶基材表面的影响较氩等离子体明显,其可使纳米铜颗粒分布均匀致密,显著增加纤维表面的粗糙度和纳米铜颗粒大小,明显提高纳米铜膜导电性能.处理后,液滴在样品表面接触角变小,镀铜织物亲水性能得到明显改善.     

超疏水导电聚酯织物的制备及其性能

为使织物兼具疏水与导电的性能,使用自制碳黑杂化同质聚酯浆料,先对聚酯织物进行导电整理,再采用溶剂诱导结晶（SINC）的方法在导电织物的表面构造微观粗糙结构,然后用甲基三氯硅烷（MTS）修饰,制备出耐水洗超疏水导电聚酯织物。研究了浆料中聚酯、碳黑的含量以及溶剂诱导结晶处理条件对织物导电及疏水性能的影响,借助场发射扫描电子显微镜、差式扫描量热仪、X射线衍射仪、接触角测量仪等对织物导电、润湿性能、耐用性及表面结构的微观形貌与结晶特点进行表征。结果表明,制备的疏水导电聚酯织物表面电阻率数量级在10 ²～10^３Ω,与水的接触角大于150°,超声水洗12 h后织物表面电阻率数量级不变,与水的接触角不小于140°。     

纺织品喷射印花

纺织品喷射印花是非接触性印花过程,这是一项无压力施加于织物上的印花新技术。即印花机械不与底布接触,印花色浆以细流微滴的形式被喷射到织物表面上。这种印花设备不需要筛网或辊筒。各种纺织品材料包括服装织物、装饰织物、床单等,都可采用这种喷射印花法。喷射印花技术的样版制作、花纹图案设计、色浆配制等都可完全由计算机控制。     

有机-无机复合膜导电织物的制备与表征

将粒径分布均匀的纳米Fe3O4颗粒、甲基三甲氧基硅烷均匀分散在由十二烷基苯磺酸钠在水中形成的微胶束中,在酸催化条件下,甲基三甲氧基硅烷在纳米Fe3O4颗粒表面发生水解缩合,制备了包覆均匀的纳米SiO2/Fe3O4磁流体。通过两步法在涤棉织物表面沉积纳米磁性颗粒与聚苯胺导电聚合物的复合膜以制备有机-无机复合膜导电织物,与聚苯胺单层膜导电织物相比,该有机-无机复合膜导电织物具有更低的电阻率,且电阻率随着纳米磁性颗粒含量的增加呈现减小趋势。     

微量墨滴在蚕丝机织物上的扩散行为

为研究喷墨印花时墨滴在蚕丝机织物上的扩散过程,以微量活性染料墨滴为研究对象,探讨蚕丝织物组织结构、墨滴体积对墨滴在织物上扩散形态的影响,分析织物预处理剂对墨滴扩散形态及扩散面积的影响。结果表明：微量活性染料墨滴在蚕丝机织物上的扩散与织物紧度有关,墨滴扩散形态在较大紧度织物上呈“十”字型;在过小紧度织物上呈椭圆形;墨滴扩散中央长度随墨滴体积增大近似呈线性增长,墨滴扩散外围长度随墨滴体积的增大先快速增长,后基本保持不变;过量尿素使墨滴的扩散区域增大,适量尿素有利于缩小墨滴的扩散区域;海藻酸钠和阳离子改性剂YS 均可降低墨滴的扩散程度,且海藻酸钠可改变墨滴的扩散形态,使墨滴由“十”字型转变为椭圆形。     

Utility of nonwovens in the production of integrated electrical circuits via printing conductive inks

This study reports on the printing of conductive inks directly onto nonwovens to produce circuits and embedded systems. The approach adopted applies polymer thick film (PTF) processing technologies directly onto compliant, flexible, nonwoven substrates. The paper reports on the characterization of various PTF conductive inks and printed transmission lines. The performance metrics related to the circuits are impacted by the ink viscosity and by the contact angle of the ink on the surface of the nonwoven structure. These parameters dictate the manner in which the ink is distributed onto and into the substrate. The manner in which ink droplets interact with the surface of the substrate determines the mechanisms responsible for both in-plane flow and through-the-plane flow of the ink.     

基于锦纶滤膜喷墨印花制备镓-铟合金液态金属电路

针对因镓-铟合金(EGaIn)液态金属(LM)具有极大的表面张力导致难以润湿基底的问题,筛选出合适的表面活性剂并利用探头超声波得到稳定的EGaIn电子墨水。利用扫描电子显微镜、透射电子显微镜、X射线光电子能谱、傅里叶红外光谱仪、X射线能量色散谱表征液态金属纳米微球的微观形貌和表面元素分布,优化得到最佳制备工艺;并通过喷墨打印在锦纶滤膜基底上成功制备图案化导电电路测试其导电性能。结果表明:用聚乙烯吡咯烷酮(PVP)作为表面活性剂,当其添加量为200 mg,超声波处理时间大于30 min时,电子墨水展现出优异的分散稳定性;当打印次数大于6,烧结后的图案化电路电阻低于150 Ω,可成功点亮发光二极管。     

The potential of electrospraying for hydrophobic film coating on foods

There is a continuous need for thinner edible coatings with excellent barrier properties, and this requires new application methods. Electrospraying is known to yield fine droplets of size down to 20 μm, giving the potential of very thin and even coatings. A single electrospraying nozzle was used to characterise droplet formation and investigate the formation of thin films on well-defined surfaces. The experimental droplet size was successfully described as a function of operational parameters and liquid properties using scaling relations. The influence of operating parameters as nozzle height and electrostatic potential were evaluated as well.Thin film deposition was experimentally investigated for sunflower oil electro-sprayed on a highly conductive (aluminium) and insulating target surface (Parafilm). For both aluminium foil and Parafilm the droplet deposition was found to be random. For aluminium foil, being a conductive target, this was expected as repellence between droplets on the surface and new droplets is low, due to charge leakage to the ground. For Parafilm, droplet repellence appeared so large that droplets deposited on larger empty spots or were even pushed away from the surface. To evaluate the film formation performance, Monte Carlo simulations were carried out, and it was found that the method is a useful tool to characterise droplet deposition and film formation characteristics.     

基于聚合物微球接枝硅油的超滑棉织物制备及其防污性能

为提高超滑织物的物理化学稳定性,首先采用乳液聚合法以乙烯基改性纳米二氧化硅(V-SiO₂)为原料制备自黏性核壳型聚合物微球,将其经浸涂-焙烘工艺组装到棉织物表面得到粗糙基底;然后利用氨基-环氧基接枝反应、氨基-羟基氢键作用将氨基硅油接枝在粗糙基底表面得到超滑织物。探究了超滑织物的疏液、防污及物理化学稳定性能。结果表明:超滑织物中超滑表面的粗糙结构由粒径为321.3 nm的微球构成,表面水滴接触角为138°;水、二甲基亚砜在超滑织物表面的滑动角分别为7°、15°;接触番茄酱、咖啡污物后,超滑表面黏附量显著减少;经200 mL以内水冲击后,超滑织物表面水、二甲基亚砜的滑动角分别小于12°、26°;在pH值为3~9条件下其表面液滴的接触角稳定在42°~49°之间。     

丝织物的大气压等离子体液相沉积处理

为提高丝织物表面的拒水、拒油性能,较好的控制沉积涂层的质量,将等离子体与液态沉积液结合,采用介质阻挡放电装置,利用高频高压电源在大气压下通入惰性气体氦（He）产生辉光放电等离子体,通过超声喷嘴将液相单体雾化并喷射入等离子体区域,使之在处理物表面上进行等离子体沉积聚合。应用此工艺对丝织物处理,将全氟庚烷单体经过超声雾化,注入大气压辉光放电区域中,实现了在丝织物表面沉积拒水性涂层。通过SEM观察和ATR-FTIR以及接触角测量,分析处理前后纤维表面形态和结构的变化,得出在不同工艺参数下丝织物表面的全氟庚烷沉积率变化规律。结果表明, 纤维表面成功沉积致密膜层,织物表面水接触角增大,拒水性能极大地改善。     

Modelling and simulation of drop spreading on fibrous porous media

Various operations in petroleum processing, textile technology, printing and composite processing involve wetting and spreading phenomena of liquids in porous media. These phenomena are being investigated using various tools, prominent among them being the spreading of a liquid drop on a porous medium. The spreading is governed by the inertial, gravitational, viscous and capillary forces and their relative importance have been studied to understand the underlying phenomena. In this work, drop spreading on heterogeneous porous media, such as composite reinforcing fabrics, has been investigated. The liquid drop spreading has been modelled in two stages: the flow of liquid on the surface of fabric and the imbibition of the liquid into the fabric due to inter-tow and intra-tow flow of the fluid. The model equations are formulated by making a hypothetical equivalent model of the fabric. The resulting equations are solved numerically. The model is used to simulate the spreading of liquid drops on glass fabrics. The drop spreading is characterized by height, contact radius and contact angle. The front of the liquid within the porous media can also be monitored through the model. Initially, a parametric study on the effect of fabric and tow porosities, the tow radius and the droplet volume on the imbibition time is presented. Finally, the model results are compared with the experimental results from literature. It is shown that the model can capture the essential features and provide insight into drop spreading on heterogeneous porous media.     

Substrate stiffness influences high resolution printing of living cells with an ink-jet system

The adaptation of inkjet printing technology for the realisation of controlled micro- and nano-scaled biological structures is of great potential in tissue and biomaterial engineering. In this paper we present the Olivetti BioJet system and its applications in tissue engineering and cell printing. BioJet, which employs a thermal inkjet cartridge, was used to print biomolecules and living cells. It is well known that high stresses and forces are developed during the inkjet printing process. When printing living particles (i.e., cell suspensions) the mechanical loading profile can dramatically damage the processed cells. Therefore computational models were developed to predict the velocity profile and the mechanical load acting on a droplet during the printing process. The model was used to investigate the role of the stiffness of the deposition substrate during droplet impact and compared with experimental investigations on cell viability after printing on different materials. The computational model and the experimental results confirm that impact forces are highly dependent on the deposition substrate and that soft and viscous surfaces can reduce the forces acting on the droplet, preventing cell damage. These results have high relevance for cell bioprinting; substrates should be designed to have a good compromise between substrate stiffness to conserve spatial patterning without droplet coalescence but soft enough to absorb the kinetic energy of droplets in order to maintain cell viability.