Graphene oxide membranes with a confined mass transfer effect for Li+/Mg2+ separation: a molecular dynamics study.

Membrane separation technology represented by graphene oxide (GO) membranes has been widely used in lithium extraction from salt lakes. It is extraordinary to study the extraction of Li+ by GO membranes from the perspective of the confined mass transfer effect. This study establishes a GO channel model with the confined mass transfer effect to closely fit the actual mass transfer process. Meanwhile, this study investigates the dynamic fluid characteristics in the separation of Li+/Mg2+ by GO membranes using molecular dynamics simulations. The results showed that the Li+/Mg2+ separation ratio is maximum at 1.0 nm layer spacing and 10% oxidation degree of the GO membrane. Water molecules form a bilayer within the channel at the appropriate interlayer channel (1 nm) and oxidation level (10%), which accelerates the ion transport rate. Furthermore, the GO oxidation group has the weakest hydrogen bonding effect on water which promotes the passage of water. Finally, the maximum separation ratio is reached due to the fact that the binding force of Li+ to water molecules in the channel is lower than that of Mg2+. The results of this study will provide theoretical consideration for the design of high-performance Li+/Mg2+ separation membranes.

Construction of MoS2/Mxene heterostructure on stress-modulated kapok fiber for high-rate sodium-ion batteries.

Molybdenum disulfide (MoS2) has possession of a layered structure and high theoretical capacity, which is a candidate anode material for sodium ion batteries. However, unmodified MoS2 are inflicted with a poor cycling stability and an inferior rate capability upon charge/discharge processes. Considering that the shape and size of anode materials play a key role in the performance of anode materials, this paper proposes a multi-level composite structure formed by the micro-nano materials based on self-assembled molybdenum disulfide (MoS2) nanoflowers, Mxene and hollow carbonized kapok fiber (CKF). The micro-nano materials can be connected to form heterojunction and agglomeration can be avoided. The load bearing of heterostructure and stress release of CKF are coordinated to form a double protection mechanism, which improves the conductivity and structural stability of hybrid materials. Based on the above advantages, it has higher specific capacity than pure MoS2, and has better rate performance (639.3, 409.5, 386.2, 372, 338, 422.8 and 434.7 mAh g-1 at the current density of 0.05, 0.1, 0.2, 0.5, 1 ,0.1 and 0.05 A·g-1, respectively). The stress-modulated strategies can provide new insights for the design and construction of transition metal sulfides heterostructures to achieve high performance sodium ion batteries.

Characteristics and bending performance of electroactive polymer blend made with cellulose and poly(3-hydroxybutyrate).

This paper describes a novel cellulose/poly(3-hydroxybutyrate) blend based electroactive polymer. The fabrication process, bending actuation test and its characteristics are investigated. To prepare this new EAP, cellulose and PHB were dissolved in trifluoroacetic acid. The solution was cast to form a film followed by depositing thin gold electrode on both sides of the film. The characteristics of the cellulose/PHB film were investigated by Fourier transform infrared spectra, scanning electron microscopy, X-ray diffraction differential scanning calorimetry, tensile test and dynamic mechanical analysis. The bending performance was evaluated in terms of free bending displacement, electrical power consumption output and lifetime test under ambient conditions. Primary results show that this cellulose/PHB blend EAP is less sensitive to humidity and it shows higher bending displacement and longer lifetime than pure cellulose EAP at room humidity condition. These results indicate that this new cellulose/PHB blend EAP has potential for many biomimetic applications.

[Research progress in electrospinning technique for biomedical materials].

Electrospinning is a very effective way to prepare scaffolds for biomedical applications. However, conventional electrospinning technique has shortcomings for this purpose. Modification studies on electrospinning technique have been conducted by more and more researchers. This paper summaries the research progress in electrospinning technique for biomedical materials.

[Preparation methods of nanocavity biomaterials with recognition specificity via template imprinting of proteins].

Nanocavity biomaterials with recognition specificity imprinted by using proteins as templates may successful serve as substitutes for antibodies, enzymes, and other native biological structures as well as cell bracket materials. It has numerous applications in biotechnology, medicine and so on. In this paper, the principle of template imprinting is introduced briefly, the specialty of template imprinting of proteins is analyzed, and the methods of template imprinting of proteins including protein entrapment, microbead surface imprinting, flat surface imprinting as well as the epitope are reviewed in details.

Biocompatibility and biodegradation of poly(hydroxybutyrate)/poly(ethylene glycol) blend films.

Using chloroform as co-solvent, a series of poly(3-hydroxybutyrate) (PHB) and polyethylene glycol (PEG) blend materials with different ratio ranging from 80 : 20 (wt %) to 20 : 80 (wt %) were prepared by solution blend. The blood-compatibility was evaluated by means of platelet clotting time test and exploring its morphological changes. The results showed that PEG played an important role in resisting platelet adhesion. With the increased addition of PEG, the clotting times became longer and the number of platelet adhesion decreased apparently. All platelets were in discrete state, no pseudopodium had been found and no collective phenomenon had been happened. The cell-compatibility was evaluated via Chinese Hamster Lung (CHL) fibroblast cultivation in vitro. The cells cultured on the matrix spread and proliferated well. With the increase of PEG content in the blend films, the number of live cells became more and more. These results indicated that PHB exhibited satisfying cell-compatibility and the addition of PEG also could improve the cell-compatibility of PHB. The biodegradation experiment indicated that the degradation of PHB/PEG was accelerated by enzyme in vitro and the blending of PEG was favorable to degradation.

[Application of biodegradable polyhydroxybutyrate in medicine and tissue engineering].

The technology of synthesis, extraction and modification of biodegradable polyhydroxybutyrate (PHB) is introduced briefly in this article. It is also summarized that the research progress in application of PHB in drug delivery and tissue engineering.

[Nano-structured scaffold materials used in tissue engineering].

Micro- and nano-structured surfaces of scaffold materials have important effects on cells' adhesion and proliferation. Nano-structured surfaces can improve cells' adhesion and biocompatibility of materials. The effects of nano-biomaterials on the development of tissue engineering and the methods of preparation of nano-biomaterials such as molecular self-assemble and template technology are discussed.