Due to the direct and sufficient contacting with the aqueous environment, the directional and continuous transport of gas bubbles on open surface without energy input will advance a variety of applications in heat transfer, selective aeration, water electrolysis, etc. Unfortunately, the behaviors of gas bubbles in aqueous environment are mainly dominated by the buoyancy moving gas bubbles upward, resulting in their difficult manipulation. Therefore, realizing the directional and continuous transport of gas bubbles on open surface still remains a great challenge. Herein, a novel strategy integrating the superaerophilic wettability with geometry-gradient structure is proposed, which can engender high driving force and low hysteresis resistance force acting on the gas bubbles. In experiment, these fabricated superaerophilic geometry-gradient polyethylene surfaces demonstrate distinguished performance of directionally and continuously transporting gas bubbles on open surfaces without energy input. In addition, the antibuoyancy bubble transportation device and the underwater bubble microreactor are successfully prepared in this manuscript, both of which illustrate the feasibility in the applications of complex environment and gas-related fields. It can be envisioned that this study will promote the understanding and development of underwater functional superwettability materials to achieve the directional and continuous transport of gas bubbles on the open surface.
Ma Hongyu Moyuan Cao Zhang Chunhui Bei Zhanlin Li Kan Yu Cunming 江雷
Advanced Functional Materials
Solution-processed semiconductor single-crystal patterns possess unique advantages of large scale and low cost, leading to potential applications toward high-performance optoelectronic devices. To integrate organic semiconductor micro/nanostructures into devices, various patterning techniques have been developed. However, previous patterning techniques suffer from trade-offs between precision, scalability, crystallinity, and orientation. Herein, a patterning method is reported based on an asymmetric-wettability micropillar-structured template. Large-scale 1D single-crystalline supramolecular arrays with strict alignment, pure crystallographic orientation, and precise position can be obtained. The wettability difference between tops and sidewalls of micropillars gives rise to the confinement of organic solutions in discrete capillary tubes followed by dewetting and formation of capillary trailing. The capillary trailing enables unidirectional dewetting, regulated mass transport, and confined crystal growth. Owing to the high crystallinity and pure crystallographic orientation with Pt atomic chains parallel to the substrate, the photodetectors based on the 1D arrays exhibit improved responsivity. The work not only provides fundamental understanding on the patterning and crystallization of supramolecular structures but also develops a large-scale assembly technique for patterning single-crystalline micro/nanostructures.
Liu Yun Feng Jiangang Zhang Bo Wu Yuchen Chen Yong 江雷
Hydrogels, composed mainly of water trapped in three dimensional cross-linked polymer networks, have been widely utilized to construct underwater superoleophobic surfaces. However, the swelling nature and instability of hydrogels under complex marine environment will weaken their underwater superoleophobicity. Herein, we synthesize structured poly (2-hydroxyethylmethacrylate) (PHEMA) hydrogels by using sandpaper as templates. The robust non-swelling of PHEMA hydrogel ensures that micro/nano-structures on the surface of PHEMA hydrogels can be well maintained. Moreover, when roughness Ra of about 3∼4 μm, the surface has superior oil-repellency. Additionally, even after immersing in seawater for one-month, their breaking strength and toughness can be well kept. The non-swellable hydrogels with long-term stable under seawater superoleophobicity will promote the development of robust superoleophobic materials in marine antifouling coatings, biomedical devices and oil/water separation.
Lin Ling Yi Hui Xinglin Guo Pengchao Zhang Chen Lie Hao Dezhao Shutao Wang 刘明杰 江雷
Science China Chemistry
Oil–water separation is a worldwide subject because of the increasing demands in numerous applications, involving separation of immiscible products from chemical reaction systems in synthetic industry. Owing to the limitations of low efficiency, high energy consumption, and multiple operations in conventional methods, membranes with special wettability have been widely developed in recent years to effectively separate various oil–water systems. However, few works on treating chemical reaction systems have been reported because of the lack of stability of current membranes in harsh environments, especially during long-term work. Herein, a continuous in situ separation of chemical reaction systems based on a special wettable porous polytetrafluoroethylene membrane is successfully conducted. The membrane possesses (1) an intrinsic (with no modification) special wettability of highly hydrophobic/oleophilic in air and superoleophilic under water and 2) an excellent long-term durability in acidic, alkaline, saline, organic, or heating environments. The in situ separation process exhibits both large separation flux (>3500 L mh) and high product purity (>99.00%) by continuously filtering synthetic products without interrupting chemical reactions, which is of great significance in industrial fields.
Xu Zhe Wang Li Yu Cunming Kan Li Ye Tian- 江雷
Advanced Functional Materials
The performance of lightweight composites are predominately determined by their cellular architectures as well as the properties of solid components. In this study, we employ a novel microlattice as the supportive architecture, which consists of a periodic array of hollow tubes connected at nodes, forming a diamond unit cell. Furthermore, diamond-structured microlattice polymer was fabricated via 3D printing technique, and conformal Ni-P thin films were subsequently coated on the polymeric substrate by electroless plating, in order to reinforce the composite strength. As a result, the strength of obtained composite is significantly enhanced with the addition of diamond particles from 1.37 MPa to 2.35 MPa. More importantly, whereas the strength of the reinforced composite is increased along with the content of diamond particles in the bath, the density of the resulting materials is decreased, leading to the significantly enhanced specific strength. We believe this work opens up an innovative way to the development of lightweight engineering materials with 3D printing.
Fan Qiongqiong Gao Yan Zhao Yungang Yang Qinglin Guo 江雷
An azobenzene with a terminal formyl group, named as (4-[(3-Formyl-4-hydroxy)phenylazo]benzene (FHPAB)), was synthesized and used to manipulate the self-assembly of diphenylalanine (FF) molecules. Two-dimensional (2D) thin slices which are composed of ordered microspheres have been constructed through supramolecular self-assembly of FF and FHPAB. The FTIR and XPS results indicate that C[dbnd]N covalent bond between FF and FHPAB was generated. Hydrogen bonding and strong π–π interaction between the planar FF-HFPAB conjugates are the driving force to form the FF-HFPAB 2D thin slices. Based on the results, a possible formation mechanism of the 2D thin slices was proposed. We also found that the FF-based 2D thin slices possess superhydrophobic properties, which is therefore an extension of the range of applications of peptide assembly.
Ma Hongchao Li Shuo Wei Yanhui 江雷 Li Junbai
Journal of Colloid and Interface Science
In this review, the binary cooperative complementary principle, which applies to two complementary states, has been proposed as a powerful law for construction of novel functional interfacial materials. The idea is to tune the distance between these two complementary components to match the characteristic length of certain physical interactions so that the cooperation between these complementary building blocks becomes dominant and thus endows the interfacial materials with unique properties. Since 2000, the binary cooperative complementarity for design of bioinspired superwettability systems has been applied by regulating the structural roughness to ≈100 nm to match the characteristic length of the hydrophobic interaction. It has been proved that the binary cooperative complementary law gains great success in constructing bioinspired superwettability systems. It is believed that much more novel interfacial materials with unique multifunctions will be generated following the binary cooperative complementary principle.
Fang Ruochen 刘明杰 Hongliang Liu 江雷
Advanced Materials Interfaces
The ballistic ejection of liquid drops by electrostatic manipulating has both fundamental and practical implications, from raindrops in thunderclouds to self-cleaning, anti-icing, condensation, and heat transfer enhancements. In this paper, the ballistic jumping behavior of liquid drops from a superhydrophobic surface is investigated. Powered by the repulsion of the same kind of charges, water drops can jump from the surface. The electrostatic acting time for the jumping of a microliter supercooled drop only takes several milliseconds, even shorter than the time for icing. In addition, one can control the ballistic jumping direction precisely by the relative position above the electrostatic field. The approach offers a facile method that can be used to manipulate the ballistic drop jumping via an electrostatic field, opening the possibility of energy efficient drop detaching techniques in various applications.
Li Ning Wu Lei Yu Cunlong Dai Haoyu Wang Ting Dong Zhichao 江雷
The development of underwater mechanically robust oil-repellent materials is important due to the high demand for these materials with the increase in underwater activities. Based on the previous study, a new strategy is demonstrated to prepare underwater mechanically robust oil-repellent materials by combining conflicting properties using a heterostructure, which has a layered hydrophobic interior structure with a columnar hierarchical micro/nanostructure on the surface and a hydrophilic outer structure. The surface hydrophilic layer imparts underwater superoleophobicity and low oil adhesion to the material, which has oil contact angle of larger than 150° and adhesion of lower than 2.8 µN. The stability of the mechanical properties stemming from the interior hydrophobic-layered structure enables the material to withstand high weight loads underwater. The tensile stress and the hardness of such a heterostructure film after 1 month immersion in seawater and pH solution are in the range from 83.92 ± 8.22 to 86.73 ± 7.8 MPa and from 83.88 ± 6.8 to 86.82 ± 5.64 MPa, respectively, which are superior to any underwater oil-repellent material currently reported.
Meng Xiangfu Wang Miaomiao Heng Liping 江雷
Liquids with low surface tension, such as petroleum, serve as the source of power for development of modern industry. Spontaneous and directional transportation of oily liquids in aqueous environment has drawn wide attentions owing to its scientific significance and practical prospect in marine petroleum exploitation and oil spill cleanup. Persistent effort has been made to the directional transportation of oil droplets under specific assistance. However, the spontaneous oriented movement of oil, especially the air/water two-phase oil delivery is still identified as a big challenge. Here, a bioinspired superoleophobic pump has been fabricated through the assembly of a superoleophobic mesh and an oil column. Depending on the directional releases of surface energy, oil droplets can be continuously collected and pumped to centimeters high without additional driving forces. The antigravity oil delivery system can realize continuous oil flow under water, even the air/water two-phase oil transportation. This work demonstrates a new mode of liquid transportation without external energy and should open a new way to design novel fluid delivery systems to realize diverse liquid transport.
Zhang Yaxin Moyuan Cao Peng Yun Jin Xu Dongliang Tian Kesong Liu 江雷
Advanced Functional Materials