液滴在超疏水形状记忆微阵列表面上定向/非定向滚动的可逆调控

利用3D打印、 模板赋形和表面修饰的方法, 制备出具有竖直结构的超疏水形状记忆微阵列. 该微阵列的竖直状态和倾斜状态能够基于形状记忆效应进行可逆调控. 当微阵列的结构发生改变, 液滴在表面的滚动状态也随之发生变化. 液滴在竖直的微阵列上表现出非定向滚动特征, 即液滴向微阵列两侧运动的滚动角是一致的. 在倾斜的微阵列上, 液滴则表现出定向运动的功能, 即液滴沿着微阵列倾斜方向上的滚动角要小于逆着阵列倾斜方向的滚动角. 因此, 本文通过调控微阵列形态实现了对液滴定向/非定向滚动的可逆调控.     

形状记忆聚合物表面水下油黏附性的可逆调控

采用模板法在形状记忆聚合物表面获得一种具有形状记忆特征的表面微结构, 在氧等离子作用下, 表面呈现低黏附的水下超疏油特性. 在外压作用下, 表面微结构发生坍塌, 失去水下超疏油性, 同时表面对油滴呈高黏附特征. 在120 ℃热处理后, 表面微结构恢复到了原始状态, 在等离子进一步作用下, 表面即可恢复到最初的低黏附水下超疏油状态. 因此通过外压、 热处理及等离子作用即可实现对表面微结构及其水下油黏附性能的可逆调控. 研究表明, 表面不同的微结构状态赋予表面不同的黏附性能, 在原始表面液滴处于低黏附的Cassie态, 而在坍塌结构表面水滴处于高黏附的Wenzel态.     

形状记忆聚合物表面微结构及黏附性能的可逆调控

采用模板法在形状记忆聚合物表面构筑了微纳米等级结构,获得了一种具有低黏附性的超疏水表面.在外压作用下,表面微结构发生坍塌,失去超疏水性,同时呈高黏附性.在120℃热处理后,表面微结构恢复到原始状态,同时表面恢复到低黏附状态.通过外压及热处理过程可实现对表面微结构及其黏附性能的可逆调控.研究结果表明,表面不同的微结构状态赋予了表面不同的黏附性能,即在原始表面上,液滴处于低黏附的Cassie态,而在坍塌结构表面上水滴处于高黏附的Wenzel态.     

超顺磁纳米弛豫开关传感器的检测原理及影响因素综述

磁弛豫开关(MRS)传感器的检测是以超顺磁氧化铁纳米粒子的磁响应信号为基础。与光学方法相比,MRS不需要对样品进行复杂的预处理而对浑浊样品中进行检测,具有良好的无损性、选择性,检测过程快速、灵敏。这使MRS传感技术在食品安全、临床医学、生化分析等方面显示出了巨大的应用潜力。本文重点对超顺磁纳米弛豫开关传感器的检测原理及影响因素进行了综述,并对其发展方向及应用前景进行了展望。     

超顺磁Fe_3O_4@PDA核-壳结构纳米粒子的制备及表征

利用多元醇高温热解法和溶液氧化法制备超顺磁四氧化三铁聚多巴胺核-壳结构纳米粒子(Fe_3O_4@PDA)。采用X射线衍射(XRD)、透射电子显微镜(TEM)、动态光散射(DLS)、傅里叶转换红外光谱(FT-IR)和热重分析(TG)等对Fe_3O_4@PDA的结构、形貌和组成进行表征。采用综合物性测试系统(PPMS)对样品的磁性能进行表征。结果表明:Fe_3O_4@PDA的尺寸可以通过氨水与多巴胺的物质的量之比和反应时间进行调控;当Fe_3O_4@PDA中Fe_3O_4的质量分数约为5%时,具有超顺磁性,磁饱和强度为3.8emu/g,比理论值高出36%。     

表面定向磁性印迹聚合物的制备及对槲皮素的选择性识别

利用硼酸功能化的磁性碳纳米管作为反应基质, 采用一种简便、 绿色的硼酸亲和表面定向印迹法制备了槲皮素磁性分子印迹聚合物, 并将其应用于银杏叶提取物中槲皮素的特异性识别. 透射电子显微镜、 X射线光电子能谱仪、 X射线衍射及振动样品磁强计测试结果表明, 制备的分子印迹聚合物具有良好的形貌和晶型结构. 吸附实验结果表明, 该分子印迹聚合物对模板分子槲皮素具有较好的吸附容量(4.57 μg/mg)、 良好的印迹效果(IF=8.44)和再生能力. 对实际中药样品银杏叶提取物的吸附实验结果表明, 所建立的方法能达到预期的槲皮素检测效果, 可作为中药有效成分槲皮素的特异性识别工具.     

磁性碳纳米管表面多金属离子印迹聚合物制备及应用

以磁性碳纳米管为载体,Co~(2+)、Cu~(2+)及Cd~(2+)等多种金属离子为模板和多巴胺为功能单体,研制一种对多种重金属离子具有高选择性吸附性能的磁性离子印迹聚合物(MIIPs)。采用红外光谱仪、透射电子显微镜、扫描电子显微镜和振动样品磁强计等技术手段对MIIPs进行了表征。采用原子吸收光谱详细研究了MIIPs的吸附性能,结果表明,MIIPs不仅具有优异的磁性能,而且对Cu~(2+)、Co~(2+)及Cd~(2+)具有快速、高效的选择识别能力,最大吸附量分别为46.08、36.35和30.65 mg/g。结合磁固相萃取和原子吸收光谱,MIIPs成功用于淤泥中Cu~(2+)、Co~(2+)及Cd~(2+)的同时分离富集,富集因子分别为18.6、13.4以及10.9。     

磁性表面分子印迹聚合物的制备及对梓醇的选择性吸附

以Fe₃O₄@SiO₂磁性复合材料为载体,梓醇为模板分子,采用沉淀聚合法合成了新型磁性表面分子印迹聚合物。优化了吸附条件,通过静态与动态吸附实验,考察了新型复合材料的吸附性能。结果表明,该材料对梓醇的最大吸附量为69.07μg/mg,印迹因子为1.97,对梓醇有优良的特异性识别能力。重复使用6次后,回收率仍在85%以上,重复利用性良好。基于此,结合磁固相萃取法,建立了应用于地黄中梓醇富集和检测的高效液相色谱法,梓醇回收率为89.5%～96.8%,相对标准偏差(RSD)≤2.0%,线性范围为0.1～1.15 mg/mL,线性相关系数R²>0.9998,检出限(LOD)为5.4 ng/mL。该新型磁性复合材料为天然产物中活性成分的富集和分析提供了一种新的预处理策略。     

超浸润形状记忆海绵的制备及油-水分离性能

基于反式 1,4-聚异戊二烯(TPI)的形状记忆性能, 以聚氨酯海绵为基底, 包覆TPI制备出了一种具有疏水超亲油特性的三维多孔形状记忆海绵. 由于这种海绵具有良好的形状记忆特性, 可以通过反复按压/恢复过程, 实现对海绵孔径在微米尺寸(约875 μm)与纳米尺寸(约450 nm)间可逆调控. 利用材料特殊的浸润特征及其可控的孔尺寸, 进一步研究了其在油-水分离中的应用. 研究结果表明, 微米尺寸大孔径海绵有利于对不相溶油-水混合物进行快速高效分离, 而纳米尺寸小孔径海绵则有利于对乳液混合物进行分离, 实现了同一材料同时满足不相溶油-水混合物及乳液体系的分离要求.     

Smart Multiple Wetting Control on ZnO Coated Shape Memory Polymer Arrays

Recently, surfaces with intelligent wetting controllability have aroused increased attention. Endowing the surface with stimuli-responsive surface chemistry and tunable surface microstructure can achieve a surface with smart wetting performances. However, almost all existing surfaces only focused on single surface chemistry or micromorphology, thus to achieve smart multiple wetting regulation is still difficult. Herein, we report a ZnO coated shape memory polymer(SMP) surface, and the surface chemistry and micromorphology can be synergistically regulated. ZnO can provide adjustable surface chemistry under UV irradiation, and SMP can offer tunable micromorphology due to its shape memory effect(SME). Based on the combined effect between the above two features, surface wetting performance can be smartly regulated among multiple states. Moreover, due to the excellent controllability of the surface, the application in directional droplet transportation was also demonstrated. This paper offers a new surface with tunability in both surface chemistry and micromorphology, and given the excellent wetting controllability, the surface is believed to be applied in a lot of fields, such as droplet manipulation, fluidic devices and selective catalysis.     

Smart Wetting Control on Shape Memory Polymer Surfaces

Control of surface wettability is very important, and can be realized by controlling surface chemistry or microstructures. Compared with surface chemistry, smart control of surface microstructure is more difficult. Recently, shape memory polymers (SMPs) have advanced to allow control of the surface microstructure and wettability, and thus, demonstrate excellent controllability and many novel functions. In this Minireview, recent achievements in wetting control on SMP surfaces with general hydrophobic, superhydrophobic, superomniphobic and superslippery properties are presented. Particular attention is paid to superhydrophobic surfaces, which display many novel functions, such as switchable isotropic/anisotropic wetting and reprogrammable gradient wetting. Furthermore, a new strategy that combines responsive molecules with the SMP microstructure is also described; this can be used to realize precise wetting control based on coordinated regulation of both surface microstructure and chemistry.     

形状记忆高分子材料的新型共混制备方法

形状记忆高分子材料(shape memory polymers,SMPs)作为一种特点突出、性能优良的智能材料具有极高的研究和实用价值,受到各国研究人员的广泛关注,新的制备方法和材料体系不断涌现,显示出巨大的发展潜力.本文总结了近年来出现的以共混方式为基础的多种重要制备方法,包括聚合物与聚合物直接熔融共混、溶液共混、借助增容剂或交联剂进行共混、通过新型微层共挤出技术进行交替层状共混、以及利用静电纺丝技术进行三维网络结构共混等.相较于化学合成方法,这些共混方法具有操作简单、原料易得、制备效率高、产品性能调节方便、制备过程更为环保等优点,并且能够得到与化学合成方法性能相同甚至更好的产品,优势突出,是今后制备形状记忆高分子材料的一大趋势.本文从这些新型共混材料的制备过程、微观结构、形状记忆性能等角度详细分析了不同方法的特点和优势.这些近年来出现的共混制备方法对于形状记忆高分子材料的发展和未来应用将是至关重要的.     

Electromagnetic Activation of Shape Memory Polymer Networks Containing Magnetic Nanoparticles

Summary: By incorporation of surface‐modified superparamagnetic nanoparticles into shape memory polymer matrices, remote actuation of complex shape transitions by electromagnetic fields is possible. The composite thermosets of oligo(ε‐caprolactone)dimethacrylate/butyl acrylate contain between 2 and 12 wt.‐% magnetite nanoparticles serving as nanoantennas for magnetic heating. It is shown that the particles are dispersed homogenously within the matrix and that the basic thermal and mechanical properties of the polymer matrix are maintained. The specific loss power of the particles is determined to be 30 W · g⁻¹ at 300 kHz and 5.0 W. During the shape transition at 43 °C, no further temperature increase is observed.

     

同时添加碳纳米管及石墨烯对热致液晶聚酯形状记忆行为及拉伸性能的影响

利用溶液共混的方法将碳纳米管(CNT)及石墨烯(G)同时加入到热致液晶聚酯中制备纳米复合材料.通过透射电镜(TEM)研究纳米粒子的分散及形貌.采用荧光光谱及拉曼光谱研究碳纳米填料与热致液晶聚酯基体之间存在π-π相互作用.利用电子万能试验机(EUTM)研究了材料的拉伸性能,由于CNT与G与基材之间作用力强,且CNT与G间的协效作用能有效地实现应力转移,同时加入CNT及G有助于提升复合材料的拉伸强度.动态热机械分析(DMA)数据表明,同时添加CNT与G对于复合材料的固定率影响不大,但会降低回复率;同时复合材料的回复应力也得到显著的提升.     

Light Responsive Microstructured Surfaces of Liquid Crystalline Network with Shape Memory and Tunable Wetting Behaviors

Using adaptive soft materials to fabricate microstructured surfaces renders them with tunable topographic feature and thus controllable physical properties. Here, light responsive microstructured surfaces are reported with shape memory and tunable wetting behaviors; the surfaces are covered with micropillar arrays and constructed by lightly crosslinked azo‐containing liquid crystalline network (LCN). UV light irradiation induces 25% contraction in length of the micropillars along their long axes and, as a consequence, the variations of topographic feature and wetting behavior of the surfaces. In addition, the LCNs exhibit shape memory properties, which can freeze the temporary topographic feature of microstructured surfaces (formed under UV irradiation and relatively high temperature) and enable application of their functionalities at mild conditions. This light responsiveness makes it feasible to remotely and precisely tune the local regions of microstructured surfaces, which should broaden the applications of adaptive surfaces in regulating the wetting, optical, and adhesion properties in selected regions.

     

New Generation of Tunable Bioactive Shape Memory Mats Integrated with Genetically Engineered Proteins

Aligned poly(l ‐lactide)/poly(methyl methacrylate) binary blend fibers and mats loaded with a chimeric green fluorescence protein having a bioactive peptide with hydroxyapatite binding and mineralization property are prepared by pressurized gyration. The effect of processing parameters on the product morphologies, and the shape memory properties of these samples are investigated. Integration of hydroxyapatite nanoparticles into the fiber assembly is self‐directed using the hydroxyapatite‐binding property of the peptide genetically engineered to green fluorescence protein. Fluorescence microscopy analysis corroborated with Fourier transform infrared spectroscopy (FTIR) data confirms the integration of the chimeric protein with the fibers. An enzyme based remineralization assay is conducted to study the effects of peptide‐mediated mineralization within the fiber mats. Raman and FTIR spectral changes observed following the peptide‐mediated mineralization provides an initial step toward a soft‐hard material transition. These results show that programmable shape memory properties can be obtained by incorporating genetically engineered bioactive peptide domains into polymer fibers.