Overview of Polyvinyl Alcohol Nanocomposite Hydrogels for Electro-Skin, Actuator, Supercapacitor and Fuel Cell.

The properties of polyvinyl alcohol (PVA) nanocomposite hydrogels influenced by nanoparticles are reviewed. Various kinds of nanoparticles with excellent mechanical and electrical properties have been introduced into PVA hydrogel to produce stretchable and conductive PVA nanocomposite hydrogel. Understanding the mechanism between the matrix of PVA hydrogel and nanoparticles is therefore critical for the development of PVA nanocomposite hydrogels. This review focuses on the nanoparticles include carbon nanotubes, graphene oxide and metal nanoparticles, and describes the effects of nanoparticles on the mechanical and conductive properties of PVA nanocomposite hydrogels. A new promising area of soft stretchable PVA nanocomposite hydrogel is highlighted for possible applications. Finally, a brief outlook for future research is presented.

Overview of Ionogels in Flexible Electronics.

Ionogels have aroused wide interests in the field of flexible electronics. The combination of solid-state networks and ionic liquids opens up thousands of possibilities for ionogels. The unique structures of ionogels endow them excellent mechanical properties, conductivity and thermal stability to approach the challenge of flexible electronic. A large number of new ionogels have been developed by different methods including the exchange of solution, polymeric ionic liquid and in-situ reactions in ionic liquids (gelation of low molecular weight gelators, self-assembly of block polymers, formation of double-network structure, ionogel nanocomposites and direct polymerization of polymerizable monomers). The aim of this review is to discuss different preparation methods of ionogels and the comparison of their advantages.

Hydrogen bonding derived self-healing polymer composites reinforced with amidation carbon fibers.

Self-healing polymer materials (SHPM) have aroused great interests in recent years. Ideal SHPM should have not only simple operations, but also high elongations at break, tensile strain and self-healing properties at room temperature. Herein, the amidated carbon fibers (CFs) reinforced self-healing polymer composites were designed by hydrogen bonding interaction between functionalized CFs and hyperbranched polymers. The amidated CFs were prepared by transformation of hydroxyl to acylamino through a one-step amidation. By introducing amidated CFs, amidated CFs self-healing polymer composites (called AD-CF) exhibited many desirable characteristics compared to pure polymer composites, such as a better elasticity, lower healing temperatures, and higher self-healing efficiencies. The stress-strain test was selected to carefully study the self-healing property of the AD-CF. The observed same recovery condition, i.e. without any mechanical breakdown after the 10 sequential cycles of cutting and healing indicates no aging of the AD-CF. The ability of AD-CF to exhibit a soft state and rapid self-healing at room temperature makes it possible for much wider applications.

Preparation of graphene/carbon nanotube-cellulose composites assisted by ionic liquids: A review.

As is well known, cellulose, as a natural polymer material with abundant reserves, plays an irreplaceable role as the major raw material in energy and chemical-related fields. With the continuous advancement of technology, native single-component cellulose is often unsatisfactory for practical applications, constructing composites is an effective means of expanding the applications. When compounded with other ingredients to prepare composites, cellulose usually needs to be dissolved and regenerated to obtain good dispersion. Current studies have revealed that cellulose is insoluble in conventional solvents, and the limited types of solvent systems that can dissolve cellulose tend to degrade the cellulose during the dissolution process, altering the cellulose properties. Ionic liquids (ILs) are a class of solvents that are capable of dissolving cellulose without adversely affecting the cellulose during the dissolution process, such as degradation. Graphene and carbon nanotubes (CNTs) are poorly dispersed and easily agglomerated by π-π stacking in general solvents, whereas ILs can effectively shield them from π-π stacking, resulting in a favorable and steady dispersion. Thus, the cellulose composites of graphene/CNTs can be prepared with the assistance of ILs. In this paper, the solubilization of cellulose by ILs and the solubilization mechanism to the preparation of cellulose composites with graphene/CNTs are reviewed, the interactions between graphene, CNTs and cellulose in the composites are elucidated, and the preparation of cellulose composites with graphene/CNTs is introduced in terms of their structure, properties and application potential.

Recent progress for silver nanowires conducting film for flexible electronics.

Silver nanowires (AgNWs), as one-dimensional nanometallic materials, have attracted wide attention due to the excellent electrical conductivity, transparency and flexibility, especially in flexible and stretchable electronics. However, the microscopic discontinuities require AgNWs be attached to some carrier for practical applications. Relative to the preparation method, how to integrate AgNWs into the flexible matrix is particularly important. In recent years, plenty of papers have been published on the preparation of conductors based on AgNWs, including printing techniques, coating techniques, vacuum filtration techniques, template-assisted assembly techniques, electrospinning techniques and gelating techniques. The aim of this review is to discuss different assembly method of AgNW-based conducting film and their advantages. GRAPHIC ABSTRACT: Conducting films based on silver nanowires (AgNWs) have been reviewed with a focus on their assembly and their advantages.

3,9-Dichloro-2,4,8,10-tetra-oxa-3,9-di-phosphaspiro-[5.5]undecane-3,9-dione.

In the title compound, C(5)H(8)Cl(2)O(6)P(2), the two six-membered rings display chair conformations. The P=O bond distances are 1.444 (2) and 1.446 (2) Å. Weak inter-molecular C-H⋯O hydrogen bonds are present in the crystal structure.

[Retrospective investigation of formation of large-scale Oncomelania snail-ridden area in Maogang Town, Songjiang District, Shanghai City].

OBJECTIVE: To explore the influencing factors of the formation of large-scale Oncomelania snail situation in Maogang Town, so as to provide the scientific evidence for improving snail surveillance in Shanghai. METHODS: The data about the geography, construction and use of floodgate, and snail status of Maogang Town and its surrounding areas, as well as the meteorology and hydrology of Songjiang District were collected and reviewed, and the factors influencing the formation of snail status were analyzed. RESULTS: The condition of water, soil and temperature in Maogang Town was suitable for snail breeding. By 1993, 75% (18/24) of the mouths flowing to Huangpu River and its branches had been built. From 1991 to 2001, the average annual precipitation of Songjiang District was 7.44% higher than the usual condition. There were two basin-wide floods occurring in 1991 and 1999, respectively. The occurrence of tides reaching or exceeding the warning level (3.50 m) of Mishidu hydrology station was positively correlated with the rainfall in the flood season (between June and September, r = 0.903, P < 0.01). Snails were found in some adjacent areas surrounding Maogang Town, and the snail situation peak occurred in early 1990s. In 2002, a large scale area (26.67 hm2) of snail habitats was detected, which was mainly distributed in the west of Maogang Town in the upstream of the Huangpu River. CONCLUSIONS: The formation of large-scale snail-breeding area in Maogang Town probably is the result of the combined action of the construction and use of floodgates, increasing rainfall, floods, tides that frequently surpass warning level of Huangpu River and the snail status of upstream areas. It is necessary to pay more attention to the data collection, analysis and utilization about schistosomiasis-related natural and social factors. In addition, regular snail surveys are suggested in schistosomiasis non-endemic areas adjacent to snail-infested area.