The applications of hydrogels are restricted by their weak mechanical properties due to the inefficient dissipation of energy in their intrinsic structures. A double-network (DN) hydrogel has been developed by combining an ionically crosslinked agar network, a covalently crosslinked acrylic acid (AAC) network, and a dynamic and reversible ionically crosslinked coordination between AAC chains and Fe 3+ ions. A model has been proposed to reveal the mechanism of the improved mechanical properties in the DN agar/AAC-Fe 3+ hydrogel. The hydrogen-bond crosslinked double helices of agar and ionic-coordination interactions of AAC-Fe 3+ serve as sacrificial bonds during large deformation to dissipate the energy while the reversible AAC-Fe 3+ interactions can be regenerated after stress relief, which greatly increases the toughness of the DN hydrogel. The prepared DN hydrogel demonstrates a remarkable stretchability with a break strain up to 3174.3%, a high strain sensitivity with a gauge factor of 0.83 under the strain of 1000%, and a good 3D printability which guarantee its various potential applications in flexible strain sensors for human motion detection, electronic skin, and soft robots.
IN BRIEF
The procurement process is notorious for being tedious and protracted due to data gathering and prolonged negotiations. With the emergence of the World Wide Web, more and more companies have established a visible presence by publicizing their products on their Web sites. If this information can be accessed automatically, ideally without the need for human intervention, the time required for procurement can be reduced. Intelligent Software Agents (ISAs) can potentially fulfill this function. In this article, an implementation of electronic sourcing using ISAs is discussed. An intelligent software agent was created using Java‐To‐GoTM, a template which extends the Java Programming LanguageTM. A client agent from the computer of the sourcing organization visits the Web sites of prospective vendors to determine if they can supply the product according to the procurement specifications. A rudimentary example of sourcing for spur gears is discussed. The demonstration conducted has proven the viability of software agents in undertaking the task of procurement in electronic commerce. Further research and development is necessary before software agents can be used more extensively in electronic procurement.
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