基于聚苯胺微胶囊的双重自修复防腐涂层

将乳液模板法、光聚合法以及苯胺的界面聚合相结合制备了负载亚麻籽油的聚苯胺微胶囊,并将微胶囊与水性环氧树脂涂层相结合来构筑了具有优异光热转化能力的双重自修复防腐涂层.当涂层受损后,微胶囊中的自修复剂亚麻籽油释放出来,对涂层进行修复;在近红外光(NIR)的照射下,聚苯胺可以有效地吸收光能并将其转化为热能,使涂层的温度高于其玻璃化转变温度,涂层破损处实现愈合.聚苯胺微胶囊的加入不仅赋予涂层优异的自修复能力,而且大大增强了其防腐能力.涂层的表面形貌、电化学与盐雾测试结果表明,聚苯胺微胶囊添加量为10%的涂层在NIR照射3 s内,可以实现快速闭合,恢复了其阻隔性能.此外,在300 h的盐雾测试后,涂层未产生任何的腐蚀产物,而纯涂层可以明显看到腐蚀现象.这种双重自修复防腐涂层的超快响应时间和高愈合效率以及优异的防腐性能具有潜在的应用价值.     

Theoretical and experimental study of phase optimization of tapping mode atomic force microscope

Phase image in tapping-mode atomic force microscope (TM-AFM) results from various dissipations in a microcantilever system. The phases mainly reflect the tip-sample contact dissipations which allow the nanoscale characteristics to be distinguished from each other. In this work, two factors affecting the phase and phase contrast are analyzed. It is concluded from the theoretical and experimental results that the phases and phase contrasts in the TM-AFM are related to the excitation frequency and energy dissipation of the system. For a two-component blend, it is theoretically and experimentally proven that there exists an optimal excitation frequency for maximizing the phase contrast. Therefore, selecting the optimal excitation frequency can potentially improve the phase contrast results. In addition, only the key dissipation between the tip and sample is found to accurately reflect the sample properties. Meanwhile, the background dissipation can potentially reduce the contrasts of the phase images and even mask or distort the effective information in the phase images. In order to address the aforementioned issues, a self-excited method is adopted in this study in order to eliminate the effects of the background dissipation on the phases. Subsequently, the real phase information of the samples is successfully obtained. It is shown in this study that the eliminating of the background dissipation can effectively improve the phase contrast results and the real phase information of the samples is accurately reflected. These results are of great significance in optimizing the phases of two-component samples and multi-component samples in atomic force microscope.     

氟氮共掺杂多孔碳纳米片的制备及其储钾性能研究

钾离子电容器是一种新型的电化学储能器件,碳基材料被认为是最有前途的储钾候选材料之一.然而,K+半径较大使得迁移速率缓慢,脱嵌过程中材料的结构易破坏,导致性能显著下降.因此,开发出低成本的碳材料来适应K+扩散的热力学与动力学需求,已成为当前发展的瓶颈.煤沥青是煤焦油经蒸馏提取液体馏分后得到的残余物,它的组成主要为稠环芳烃,具有高的含碳量、可塑性好、资源集中、价格低廉等显著优点,是一种优质的碳基材料前驱体.鉴于此,本工作采用煤沥青作为碳源、聚四氟乙烯为氟源,氯化钠为模板剂,通过直接高温碳化的策略制备了氟氮共掺杂的多孔碳纳米片(FNCPC).研究表明,纳米片层的结构设计有效缩短了离子的传输路径, F、N共掺杂拓宽了碳的层间距,缓解了体积膨胀问题,并且形成更多的表面缺陷,可为K+的存储提供更多的反应活性位点.此外,电化学动力学分析和密度泛函理论(DFT)表明,FNCPC具备显著的赝电容特性和强的对K吸附能.得益于结构和化学性质的协同优化,FNCPC负极展现出优异的储钾能力(2 A·g^–1电流密度下具有212.8 mAh·g^–1的比容量)和循环稳定性....