Ni-Nb粉末与SiC陶瓷界面润湿特性研究

研究了Ni—Nb金属粉末与SiC陶瓷的界面润湿特性，结果表明，增加Nb含量、升高温度或延长保温时间，系统润湿性均得到改善。对润湿系统界面区域微观结构的SEM、EDS分析表明，由于活性元素Nb的加入，在一定的温度、时间和气氛等条件下，焊料与陶瓷发生相互问的溶解、扩散和反应，其接触界面发生改变，此时测得的润湿角已不是Ni—Nb液滴/SiC陶瓷村底的接触角，而是新生成的固液界面间的接触角。界面区域具有连续结构的Ni-Si化合物的生成对于Ni—Nb／SiC陶瓷体系的润湿起重要作用。     

可控硫酸溶液和表面活性剂作用下铜矿石的液体扩散行为及表面润湿性

为了揭示表面活性剂对提高铜矿表面润湿性的潜在作用,采用高速摄像和图像处理方法,对含表面活性剂硫酸溶液的液滴扩散行为进行了可视化研究,并对固液相互作用进行了探讨.结果表明,液体表面张力和矿石表面粗糙度是影响表面润湿性的主要因素.通过定量铺展面积、铺展系数和接触角,揭示了硫酸溶液浓度和表面活性剂对矿石表面润湿性的影响.液滴...     

甲醇/水混合溶液在蝴蝶翅表面的润湿行为

使用视频光学接触角测量仪和扫描电子显微镜研究了甲醇/水混合溶液在蝴蝶翅表面的润湿行为,根据Cassie方程分析了甲醇对蝴蝶翅表面的润湿机理。结果表明,蝴蝶翅表面具有较强的疏水性(蒸馏水接触角为134.0°～159.2°)和疏甲醇性(45%甲醇溶液接触角为91.3°～128.5°)。甲醇溶液在32种蝴蝶翅表面润湿和铺展的临界体积分数分别为50%和70%。在黄钩蛱蝶(Polygonia c-aureum)翅表面,当甲醇体积分数<45%时,液滴在纳米级结构上的体相力大于表面力,液体填满纳米级缝隙,而在微米级结构上体相力小于表面力,液滴由微米级结构支撑,翅表面不发生润湿;当45%≤甲醇体积分数<65%时,液滴在纳/微米级结构上的体相力均大于表面力,液滴塌陷;当甲醇体积分数≥65%时,翅表面发生润湿,由复合接触转为湿接触。     

介电层表面纳米织构化及其电润湿行为影响研究

为了更好地调控液滴的形状,探讨了纳米织构化介电层表面的电润湿行为.采用刻蚀和软压印方法在导电基底上实现了紫外光固化聚合物(NOA61)介电层的纳米织构;搭建了实验平台,观察对比了厚度相同而形貌不同的介电层表面的电润湿响应.结果表明,平整光滑介电层在电压较低时表现为不可逆的电润湿响应,当方波电压大于200V时则表现为可逆的电润湿响应;网格纳米织构介电层的可逆转变临界电压为350V,而纳米锥织构介电层则在高达500V以上直至产生接触角饱和现象也仍保持不可逆的电润湿响应;几种介电层的饱和接触角趋于一致.之所以水滴在纳米织构化的介电层表面发生了不可逆的Wenzel接触模式润湿转变,是由于水滴在电场下与织构微观表面之间具有较高的粘滞作用.     

适用于致密砂岩储层气湿反转剂筛选与评价

通过接触角测试和可注入性实验对非离子型表面活性剂、含氟阳离子型表面活性剂、氟碳纳米液在致密砂岩储层的气润湿性改变能力和注入性进行评价。结果表明,相对于其他化学剂,氟碳纳米液CRS⁃850具有较好的气润湿反转效果,岩心表面接触角从45.6°增加到92.1°,由强水湿转变为气相润湿;处理前岩心自吸盐水量0.360 8 g,处理后自吸量下降至0.020 6 g,岩心自吸量下降幅度达98.85%。最大自吸速率从0.053 g/min下降至0.002 g/min;气润湿反转剂显著提高岩心内部液相渗流能力,增加气驱渗透率,岩心气驱渗透率恢复效果显著,在气驱盐水基础上提高了501.69%~673.91%,表明气润湿反转剂有利于致密砂岩储层解除液相伤害。     

单晶硅表面纳米结构润湿行为的分子动力学模拟

通过在单晶硅100晶面上去除不同数量的硅原子,构建出不同形貌的表面纳米结构以及二级结构;同时,采用分子动力学模拟的技术,研究单晶硅不同表面纳米结构润湿行为。模拟结果得出,具有纳米结构的单晶硅表面疏水性优于平整单晶硅表面。经过模拟,未去除硅原子的单晶硅结构表观接触角为72.02,呈亲水性;光栅结构表观接触角为103.45,方柱结构表观接触角为123.17,梯形结构表观接触角为150.4,二级结构表观接触角为152.25,其中二级结构的疏水性能最优。此外,具有纳米结构的单晶硅粗糙表润湿行为更为接近于Cassie-Baxter模型,接触模式为空气柱模型。     

水平板上固着碳纳米管燃油液滴的蒸发特性

以正十四烷（C14）为基液,表面活性剂溴化十六烷三甲基铵（CTAB）为助溶剂,采用两步法配制分别含有20、50 nm碳纳米管（CNT）的纳米燃油. 分析比较基液燃油与纳米燃油的黏度特性,采用接触角测量仪记录燃油液滴在加热平板上的蒸发变形,探究不同粒径及质量浓度的CNT对正十四烷燃油液滴蒸发特性的影响. 研究表明,纳米粒子的加入增加了基液的黏度,并且黏度随着纳米粒子质量浓度增大或粒径减小而增加. CNT纳米燃油液滴蒸发过程符合部分润湿状态下单组分液滴蒸发的一般规律. 在液滴蒸发定接触线阶段,纳米燃油导热系数增强,液滴从外界吸收的热量加快向液体内部传递,延滞了液滴边缘处（三相线处）液体分子的挥发. 纳米粒子在液滴边缘处沉积,阻滞了接触线向内收缩,增加了液滴在定接触线阶段蒸发的持续时间,纳米燃油在此阶段的蒸发速率比基液燃油低,且蒸发速率的差异随燃油中纳米粒子数量的增多而加大. 在定接触角与混合蒸发阶段,“自销钉”效应阻滞接触线收缩,液滴与底板的接触面积较大,液滴中纳米粒子质量浓度的增加使液滴吸收更多的热量,在后2个蒸发阶段,纳米燃油的蒸发速率明显加快,大于基液燃油的蒸发速率. 在整个蒸发过程中,纳米燃油的平均蒸发速率高于基液燃油.     

纳米结构中浸入特性的非平衡分子动力学模拟

为明晰复杂纳米通道内流体流动规律,采用分子动力学方法研究压力驱动作用下不同润湿性纳米通道的液态水浸入特性。建立液态水/不同润湿性纳米通道的非平衡态分子动力学模型,研究驱动压大小、壁面润湿性及纳米粗糙元结构对液态水浸入特性的影响规律。模拟结果表明:相同驱动压条件下,液态水易于浸入亲水性纳米结构通道内,相比于光滑纳米通道,纳米粗糙元结构凸显液态水的表面张力作用,提高液态水持续浸入纳米通道的驱动压;纳米粗糙元结构对液态水浸入速度以及密度分布均有影响,纳米粗糙元距离入口处越近,浸入过程的阻力越大,即液态水浸入纳米通道内的体积通量越小,研究结果为明晰复杂纳米通道内液态水输运的微观机理提供理论基础。     

纳米结构中浸入特性的非平衡分子动力学模拟

为明晰复杂纳米通道内流体流动规律,采用分子动力学方法研究压力驱动作用下不同润湿性纳米通道的液态水浸入特性。建立液态水/不同润湿性纳米通道的非平衡态分子动力学模型,研究驱动压大小、壁面润湿性及纳米粗糙元结构对液态水浸入特性的影响规律。模拟结果表明:相同驱动压条件下,液态水易于浸入亲水性纳米结构通道内,相比于光滑纳米通道,纳米粗糙元结构凸显液态水的表面张力作用,提高液态水持续浸入纳米通道的驱动压;纳米粗糙元结构对液态水浸入速度以及密度分布均有影响,纳米粗糙元距离入口处越近,浸入过程的阻力越大,即液态水浸入纳米通道内的体积通量越小,研究结果为明晰复杂纳米通道内液态水输运的微观机理提供理论基础。     

烟煤煤尘润湿性与无机矿物含量的关系研究

为了研究我国主要产煤烟煤润湿特征,探究其所含无机矿物与煤尘润湿性之间的定量关系,选取具有代表性的2种煤质共8个煤样进行煤质灰分测定和液固界面动态接触角滴液系统测定实验,借助NICOLET-380傅立叶变换红外光谱仪和D/max2500PC型X-射线衍射仪,对样品煤尘表面主要含Si矿物代表基团特征和含量进行分析.结果表明:煤中无机物相组成特征是煤灰分增强烟煤润湿性的根本原因,即无机矿物中以石英为代表的原生矿物是提高煤尘亲水能力的最主要因素,其自身含量与润湿接触角呈线性关系,相关系数达0.855 68.     

Transition of super-hydrophobic states of droplet on rough surface

Twelve samples with periodic array square pillars microstructure were prepared on the silicon wafer by plasma etching techniques, on which space b of the square pillars increased from 5 to 60 m. In order to study the effect of b on the wettability of the rough surface, the effects of apparent contact angle (CA) and sliding angle (a) of the droplet on the rough surface were measured with the contact angle meter. The results show that the experimental values of CA well agree with the classical wetting theory and a decreases with the increase of b. Two drop shapes exist on the samples' surface, corresponding to the Cassie state and the Wenzel state respectively. The contact state in which a drop would settle depends typically on the size of b. On the role of gravitation, the irreversible transition of a drop from Cassie state to Wenzel state should occur at a certain space of the square pillars. Since the transition has implications on the application of super-hydrophobic rough surfaces, theoretically, the prediction of wetting state transition on square pillar array micro-structured surfaces provides an intuitionistic guidance for the design of steady superhydrophobic surfaces.     

改性石英砂的润湿性能研究

对经过改性处理之后的普通石英砂的润湿性能进行了研究。实验采用滴水穿透时间法（WDPT）、酒精溶液入渗法（MED）、接触角测定法三种方法。通过这三种方法来定性和定量地描述其润湿性能。实验结果表明：直接经过酸化处理的石英砂与经过硅烷化处理的石英砂的润湿性能有着明显的改变,前者较普通石英砂表现更为亲水,而后者表现出斥水性。此研究为用石英砂模拟不同润湿性能土壤提供了表面改性方法以及前期的理论准备。     

水中油滴在不同润湿性表面上的铺展行为研究

通过高速显微实验与理论推导相结合的方式,从微观角度研究了水中油滴在光滑铜板基底的铺展行为;通过物理和化学修饰,实现了黄铜表面水下超亲油到超疏油的可控调节,观察了油滴浮升到修饰黄铜表面后铺展长度随时间变化的差异.与空气中液滴撞壁铺展不同,水中油滴的铺展需要同时考虑液滴铺展过程中周围流体对液滴铺展的黏性作用,其在基底表面的...     

Influence of laser geometric morphology type on SiC surface wettability

To obtain effective surface morphology to control surface wettability, this work investigated the influence of protuberant and concave morphology, which are respectively represented by circle-dimpled and micro-square-convex morphology, on surface wettability. The geometric morphologies were processed on silicon carbide (SiC) surfaces by a laser-marking machine, and surface wettability was monitored by the measurement of contact angles using the sessile drop method. Correlation analysis between contact angles and morphology parameters was conducted to determine the extent of influence. The results showed that the circle-dimpled diameter had a significant influence on surface wettability, whereas grooved width did not. Additionally, the depth of dimples and grooves exerted less influence on controlling wetting behaviors. In addition, surface wettability transformed from a superhydrophilic state to a hydrophobic state on micro-square-convex surfaces; contact angles on circle- dimpled surfaces showed a relatively slow transformation, though the surface wettability also underwent the state change.     

Liquid droplet movement on horizontal surface with gradient surface energy

A surface with gradient surface energy was fabricated on a silicon wafer by using the chemical vapor deposition (CVD) technology with the dodecyltrichlorosilane (C12H25Cl3Si) vapor which was adsorbed chemically on the surface of the silicon wafer to form a self-assemble monolayer (ASM) and thus a gradient profile of wettability. The microscopic contours of the gradient surface were measured with Seiko SPA400 atom force microscope (AFM). And the surface wettability profile was characterized by the sessile drop method, measuring the contact angle of fine water droplets that lay on the gradient surface, to represent the distribution of the surface energy on the surface. Using a high-speed video imaging system, the motion of water droplet on the horizontal gradient surface was visualized and the transient velocity was measured under ambient condition. The experimental results show that the liquid droplets can be driven to move from hydrophobic side to hydrophilic side on the horizontal gradient surface and the velocity of droplet can reach up to 40 mm/s. In addition, the motion of the water droplet can be generally divided into two stages: an acceleration stage and a deceleration stage. The droplet presents a squirming movement on the surface with a lower peak velocity and a larger extent of deceleration motion. And the static advancing contact angle of the droplet is obviously larger than the dynamic advancing contact angle on the gradient energy surface.     

Effect of roughness on wettability and floatability: Based on wetting film drainage between bubbles and solid surfacesOA

Wetting film thinning measurement was introduced to clarify the wettability and floatability of solid surfaces with varying roughness. The wettability was quantified using the contact angle measurement combined with the dynamic force microbalance test between solid surfaces and water droplets, while the floatability was investigated by the bubble-solid surface dynamic attachment observation and the induction time measurement. The results show that the water contact angles reduce(14.53°, 12.74°, ...     

飞秒激光制备航空用铝靶材表面润湿功能微纳结构的研究

近年来,飞行器润湿功能外壳防冰技术以其不消耗能源、几乎不增加额外体积和质量等优点备受世界各国科学家及工程师的关注.铝合金材料一直广泛的应用于民用飞行器,特别是飞机外壳和骨架,然而原有外壳材料表面润湿特性表现中庸.通过飞秒激光微纳结构制备技术,可以有效改变其表面的润湿特性.利用飞秒激光在不同实验条件下,制备了两种典型的微纳复合结构,实验结果表明,柱型微纳结构以独特的双尺寸复合结构所提供的空气气模实现了表面超疏水特性.而沟槽型微纳结构以开放腔毛细管效应为原动力,使其展现了超亲水特性,并具备定向输水功能.这些润湿功能的实现对航空飞行器防冰技术的发展有着重要的应用意义.     

液滴撞击疏水球面的高速可视化实验研究

基于高速可视化成像实验平台,对液滴撞击疏水球面进行了实验研究,观测并定量表征了液滴撞击过程的动态行为,分析了液滴撞击速度和液滴-球体直径比对液滴撞击行为特征的影响。实验结果表明:撞击过程可分为铺展、回缩和振荡3个阶段;液滴在接触球面后沿接触点向四周均匀铺展,达到最大铺展后回缩,之后进行多次铺展-回缩的振荡过程,直到动能与表面能达到平衡状态,液滴在球面上趋于静止;液滴撞击速度的增加增大了液滴惯性力,促进液滴的铺展,使液滴达到平衡稳定状态所需要的时间增加;液滴-球体直径比对液滴撞击行为特征影响较小。     

Mechanism of micro-wetting of highly hydrophobic coal dust in underground mining and new wetting agent development

The internal mechanism of the high hydrophobicity of the coal samples from the Pingdingshan mining area was studied through industrial, element, and surface functional group analysis. Laboratory testing and molecular dynamics simulations were employed to study the impact of three types of surfactants on the surface adsorption properties and wettability of highly hydrophobic bituminous coal. The results show that the surface of highly hydrophobic bituminous coal is compact, rich in inorganic mine...