Herein, synthetic graphite materials with hierarchical pores and large specific surface area were prepared by one-step impregnation with lignite as the carbon source, H2SO4 as the oxidant, and H3PO4 as the activator.
Conventional machines rely on rigid, centralized electronic components to make decisions, which limits complexity and scaling. Here, we show that decision making can be realized on the material-level without relying on semiconductor-based logic. Inspired by the distributed decision making that exists in the arms of an octopus, we present a completely soft, stretchable silicone composite doped with thermochromic pigments and innervated with liquid metal. The ability to deform the liquid metal couples geometric changes to Joule heating, thus enabling tunable thermo-mechanochromic sensing of touch and strain. In more complex circuits, deformation of the metal can redistribute electrical energy to distal portions of the network in a way that converts analog tactile ‘inputs’ into digital colorimetric ‘outputs’. Using the material itself as the active player in the decision making process offers possibilities for creating entirely soft devices that respond locally to environmental interactions or act as embedded sensors for feedback loops.
Supramolecular chemistry has provided versatile and affordable solutions for the design of intelligent soft materials, but it cannot be applied in stiff materials. This paper describes a new concept for the design of high-performance supramolecular thermosets by using the noncovalent cation-π interaction as cross-linking. These supramolecular thermosets are a class of infusible and insoluble stiff polymers having excellent mechanical properties even at temperatures exceeding 300 °C. The cation-π interaction can be locally and reversibly installed and removed by aqueous treatments at high or low pH, respectively. Local manipulation of cross-linking confers these thermosets with multiple stimuli-responsive functions, such as recyclability, healability, adhesion, and nondestructive detection of cross-linking and mechanical properties.
A series of benzocyclobutene (BCB) polymers derived from a new readily available monomer, 4-(1 0 ,1 0 -dimethyl-1 0 -vinyl) silylbenzocyclobutene (4-DMVSBCB), were conveniently prepared by radical and anionic polymerization. The homo-and co-polymerization results show that the reactivity of 4-DMVSBCB in anionic polymerization is relatively higher compared with radical polymerization. The molecular weight of 4-DMVSBCB polymers and content of 4-DMVSBCB can be controlled by anionic copolymerization. The introduction of rigid and crosslinkable BCB building blocks in side chains and carbosilanes in molecule gives rise to insulating materials with good film-forming property, smooth and flat film surface, and low-dielectric constants of 2.41-2.45, as preserving good thermal stability. FIGURE 8 TGA spectrum of highly crosslinked poly(4-DMVSBCB) under nitrogen atmosphere.FIGURE 9 TGA spectrum of highly crosslinked poly(4-DMVSBCB) under oxygen atmosphere.FIGURE 7 AFM spectra of pre-crosslinked and highly crosslinked poly(4-DMVSBCB) film. ARTICLE NEW POLYMERS DERIVED FROM 4-DMVSBCB MONOMER, YANG ET AL. 389
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