Amorphous red phosphorus incorporated with pyrolyzed bacterial cellulose as a free-standing anode for high-performance lithium ion batteries.

Amorphous red phosphorus/pyrolyzed bacterial cellulose (P-PBC) free-standing films are prepared by thermal carbonization and a subsequent vaporization-condensation process. The distinctive bundle-like structure of the flexible pyrolyzed bacterial cellulose (PBC) matrix not only provides sufficient volume to accommodate amorphous red-phosphorus (P) but also restricts the pulverization of red-P during the alternate lithiation/delithiation process. When the mass ratio of raw materials, red-P to PBC, is 70 : 1, the free-standing P-PBC film anode exhibits high reversible capacity based on the mass of the P-PBC film (1039.7 mA h g-1 after 100 cycle at 0.1C, 1C = 2600 mA g-1) and good cycling stability at high current density (capacity retention of 82.84% after 1000 cycles at 2C), indicating its superior electrochemical performances.

Solid-State Fluorescence of Fluorine-Modified Carbon Nanodots Aggregates Triggered by Poly(ethylene glycol).

Solid-state fluorescent carbon quantum dots (QDs) can be used for the encryption of security information. Controlling the dispersion and aggregation of the QDs is crucial for switching their solid-state fluorescence "on" and "off." The use of polymers has been proposed to slightly separate the QDs inside aggregates to trigger their fluorescence. However, the complex interactions between the QDs and flexible polymer chains make this process challenging. Here, fluorine-modified carbon nanodots (FCDs) were used in a solution as the printing ink. After printing, the FCDs were aggregated on paper via hydrogen bonds, thereby quenching the fluorescence. After a poly(ethylene glycol) (PEG) treatment, the FCDs exhibited yellow solid-state fluorescence due to an increased interdot spacing. The fluorescence intensity and emission wavelength could be tuned by varying the molecular weight and quantity of PEG used. Finally, we demonstrated a high-resolution encryption and decryption system based on the PEG-triggered fluorescence of FCDs.

Tetracarboxylated Azobenzene/Polymer Supramolecular Assemblies as High-Performance Multiresponsive Actuators.

Multistimuli-responsive polymers are materials of emerging interest but synthetically challenging. In this work, supramolecular assembly was employed as a facile and effective approach for constructing 3,3',5,5'-azobenzenetetracarboxylic acid (H4abtc)/poly(diallyldimethylammonium chloride) (PDAC) supramolecules. Structural transformations of H4abtc can be induced by light, mechanical force, and heat and influenced by free volume. Thus, the fabricated free-standing H4abtc/PDAC film underwent bending/unbending movements upon treatment with light, humidity, or temperature, as asymmetric structural transformations on either side of the film generated asymmetric contraction/stretching forces. Fast rates of shape recovery were achieved for the film on exposure to gently flowing humid nitrogen. The bending/unbending motions are controllable, reversible, and repeatable. Hence, this light-, humido-, and thermo-responsive film has great potential in device applications for advanced functions.

Using multiple hydrogen bonding cross-linkers to access reversibly responsive three dimensional graphene oxide architecture.

Three-dimensional (3D) graphene materials have attracted a lot of attention for efficiently utilizing inherent properties of graphene sheets. However, 3D graphene materials reported in the previous literature are constructed through covalent or weak non-covalent interactions, causing permanent structure/property changes. In this paper, a novel 3D graphene material of dynamic interactions between lamellas with 2-ureido-4[1H]-pyrimidinone as a supra-molecular motif has been synthesized. This 3D graphene material shows enhanced sheet interactions while the cross-linking takes place. With proper solvent stimulation, the integrated 3D graphene material can disassemble as isolated sheets. The driving force for the 3D structure assembly or disassembly is considered to be the forming or breaking of the multiple hydrogen bonding pairs. Furthermore, the 3D material is used as an intelligent dye adsorber to adsorb methylene blue and release it. The controllable and reversible characteristic of this 3D graphene material may open an avenue to the synthesis and application of novel intelligent materials.