Summary: A drop‐on‐demand ink‐jet printer has been used to print a silver‐organic solution onto glass substrates. Conductive silver tracks were obtained by heat treatment of the ink‐jet printed deposits at temperatures ranging from 125 °C–200 °C in air. Resistivity values were found to have dropped to two to three times the theoretical resisitivity of bulk silver after temperatures of 150 °C and above were used.
The use of the molecular imprinting technique to produce polymers with high specificity for a given “molecular template” has undergone a rapid and expansive evolution since the inception of the idea over half a century ago. It was only a matter of time before the seemingly inevitable “marriage” of this concept with another modern research obsession, the generation of “smart” polymers, capable of reacting quickly, accurately and reproducibly to changes in their environment. Many advances have since been made, concerning the quality and diversity of these systems and polymers responsive to temperature, pH and a host of other environmental cues now exist. This article provides a succinct overview of the process and outcomes of “smart” molecular imprinting, followed by a detailed assessment of recent developments and applications in such field.
An amylose‐grafted chitosan has been synthesized by a chemoenzymatic method according to the following two reactions. First, maltoheptaose is introduced to chitosan by a reductive amination using sodium cyanotrihydroborate in a mixed solvent of 1.0 mol · L−1 aqueous acetic acid and methanol at room temperature to produce a maltoheptaose‐grafted chitosan that has a well‐defined molecular structure. A phosphorylase‐catalyzed enzymatic polymerization of α‐D ‐glucose 1‐phosphate is then performed from the maltoheptaose‐grafted chitosan to obtain the amylose‐grafted chitosan. This material does not dissolve in any solvent, e.g., aqueous acetic acid and dimethyl sufoxide, which are good solvents for chitosan and amylose, respectively.
The theoretical postulations of mass spectral quantities and distributions of the three dynamic combinatorial libraries (DCLs) of mechanically interlocked dendrimers ([4]rotaxanes, molecular weight up to 8 800 kDa) have been investigated. The number of different dendrimers in the three library mixtures is 4, 10, and 20. The theoretical postulations involve their macroconstants in a combination with statistical distribution, binding constant, steric, and hydrophobic effects. We found out that the mass spectral intensities which relate to the dendrimer quantities in a competitive mixture are not random, but with a predictable trend in terms of their macroconstants. This postulation agrees significantly well with most of the experimentally determined mass spectral intensities in the dendrimer mixtures.
Summary: A new strategy was developed to prepare disorderly exfoliated nanocomposites, in which a soft siloxane surfactant with a weight‐average molecular weight ( ) of 1 900 was adopted to modify the clay. The modified clay slurry was then mixed with silicone rubber by hand, and exfoliation was achieved. The proposed mechanism thereof was verified by TEM and XRD. The physical entanglement of the soft siloxane surfactant plays a vital role in the diffusion and intercalation of the matrix molecules during the compounding of the slurry‐polymer mixture. This simple method is applicable to other silicone‐based materials reinforced by clay.
TEM micrograph of silicone rubber/clay‐sil nanocomposite. 相似文献
The crossover from small‐molecule to polymer behavior in realistic models of PI at temperatures well above the glass transition is investigated by means of MD simulations. The molar masses range from the monomer to = 6 800 g · mol−1 which is far from the critical value for entanglement in PI. It is shown that at this temperature the non‐Gaussian parameter almost vanishes in the Q‐range studied. This implies Gaussian behavior in almost all the Q‐range. From the mean square displacement and the incoherent scattering function behavior a smooth transition from the microscopic regime to the Rouse dynamics is observed. The Rouse behavior is achieved at chain molecular weights of about 1 000 g · mol−1, which corresponds to 14 monomer units.
Transparent film materials with excellent mechanical and thermal properties were elaborated by drying a latex suspension of armored polymer/Laponite composite particles. Low‐temperature TEM observation of ultrathin cross‐sections of the films indicated a unique network morphology characterized by a “honeycomb” distribution of the Laponite platelets remindful of the original particles morphology.
Specific losses of water are observed from the molecular anions of monoximes of α-diketones. Labelling studies, kinetic energy release values and the +E spectra of ions have been used to aid in the elucidation of the fragmentation pathways. It is proposed that the majority of ions have α-keto nitrile structures. 相似文献
Supramolecular poly(vinyl acetate) PVAc 3‐arms stars were successfully generated by Reversible Addition–Fragmentation chain Transfer (RAFT)‐polymerized chains bearing hydrogen‐bonding heterocomplementary associating units. Chain Transfer Agents (CTA) bearing thymine‐ and diaminopyridine‐based units were first synthesized and proved to mediate efficiently the polymerization of VAc. The binding ability of the chains in solution was then demonstrated by 1H NMR and GPC measurements, proving the formation of the supramolecular stars.
We describe the fabrication of a biomimically designed superhydrophobic poly(ε‐caprolactone) surface, which was obtained using a modified electrostatic process. The fabricated surface exhibits a micron‐sized pyramid structure consisting of accumulated droplets and nanofibres. By using this simple one‐step process, we can achieve a superhydrophobic surface having both a high water contact angle and low threshold sliding angle, similar to that of the superhydrophobic plant leaf.
A series of selenophene oligomers incorporating conjugated fluorinated phenylene units have been synthesised as potential semiconductor materials for organic field‐effect transistors (OFETs). X‐ray crystallography shows that the molecules are held in close proximity by several short intermolecular contacts, making them ideal candidates for OFET applications.
