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1.
Macromol Rapid Commun ; 40(5): e1800252, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30027623

RESUMO

Novel graphene-oxide-reinforced silicone composites (GOSC) are prepared by in situ polymerization of silanes and low concentrations (<0.15 wt%) of silylated GO (SGO). After modification, the distances of the SGO nanosheets are successfully increased from 0.72 to 0.87 nm. Compared with GO, the SGO shows better dispersibility in organic solvents as well as remarkably enhanced decomposition temperature (T d improved by 100 °C). After covalently grafting onto silicone resins via in situ polymerization, the obtained GOSC exhibits greatly enhanced thermal stability (T d up to 400 °C and T g improved by 3-5 °C), increased storage modulus, loss modulus, and complex viscosity. The morphology, microstructure, interfacial adhesion of the developed GOSC coatings were carefully investigated. The GOSC coatings on metal exhibit good transparency (up to 90%), hydrophobicity, and excellent anticorrosion capability. This work provides a new strategy for developing high performance graphene-based silicone composite materials.


Assuntos
Grafite/síntese química , Polimerização , Silicones/síntese química , Varredura Diferencial de Calorimetria , Corrosão , Grafite/química , Espalhamento a Baixo Ângulo , Silicones/química , Termogravimetria , Difração de Raios X
2.
ACS Nano ; 17(11): 9748-9762, 2023 Jun 13.
Artigo em Inglês | MEDLINE | ID: mdl-37171107

RESUMO

As the Si-based transistors scale down to atomic dimensions, the basic principle of current electronics, which heavily relies on the tunable charge degree of freedom, faces increasing challenges to meet the future requirements of speed, switching energy, heat dissipation, and packing density as well as functionalities. Heterogeneous integration, where dissimilar layers of materials and functionalities are unrestrictedly stacked at an atomic scale, is appealing for next-generation electronics, such as multifunctional, neuromorphic, spintronic, and ultralow-power devices, because it unlocks technologically useful interfaces of distinct functionalities. Recently, the combination of functional perovskite oxides and two-dimensional layered materials (2DLMs) led to unexpected functionalities and enhanced device performance. In this paper, we review the recent progress of the heterogeneous integration of perovskite oxides and 2DLMs from the perspectives of fabrication and interfacial properties, electronic applications, and challenges as well as outlooks. In particular, we focus on three types of attractive applications, namely field-effect transistors, memory, and neuromorphic electronics. The van der Waals integration approach is extendible to other oxides and 2DLMs, leading to almost unlimited combinations of oxides and 2DLMs and contributing to future high-performance electronic and spintronic devices.

3.
Polymers (Basel) ; 11(11)2019 Nov 08.
Artigo em Inglês | MEDLINE | ID: mdl-31717323

RESUMO

Organic materials have gained considerable attention for electrochromic (EC) applications owing to improved EC performance and good processability. As a class of well-recognized organic EC materials, viologens have received persistent attention due to the structural versatility and property tunability, and are major active EC components for most of the marketed EC devices. Over the past two decades, extensive efforts have been made to design and synthesize different types of viologen-based materials with enhanced EC properties. This review summarizes chemical structures, preparation and EC properties of various latest viologen-based electrochromes, including small viologen derivatives, main-chain viologen-based polymers, conjugated polymers with viologen side-chains and viologen-based organic/inorganic composites. The performance enhancement mechanisms are concisely discussed. The current marketed viologens-based electrochromic devices (ECDs) are briefly introduced and an outlook on the challenges and future exploration directions for viologen-based materials and their ECDs are also proposed.

4.
ACS Appl Mater Interfaces ; 5(23): 12275-82, 2013 Dec 11.
Artigo em Inglês | MEDLINE | ID: mdl-24256294

RESUMO

A novel biomass-based nitrogen-doped free-standing fused carbon fibrous mat was fabricated from lignin-polyethylene oxide (PEO) (90:10) blend via electrospinning followed by carbonization and thermal annealing in the presence of urea. The morphology and structure of the carbon fibers were characterized by field-emission scanning electron microscopy, Raman spectroscopy, X-ray photoelectron spectroscopy, and elemental analysis, and their electrochemical properties were investigated for the first time as anode in lithium ion batteries (LIBs). The fused carbon fibers without nitrogen doping exhibited high specific capacity up to 445 mA h g(-1) at a current density of 30 mA g(-1) (comparable to polyacrylonitrile (PAN) derived carbon nanofibers) and good cyclic stability at different current rates. After thermal annealing in the presence of urea, the charge capacity was further improved to as high as 576 mA h g(-1) and still maintained a good capacity of about 200 mAh g(-1) even at a high current rate of 2000 mA g(-1). This research demonstrates the great promise of lignin-derived nanocarbon materials for applications in energy storage systems.

5.
Chem Pharm Bull (Tokyo) ; 55(7): 1011-3, 2007 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-17603191

RESUMO

Newly synthesized polymer-supported chiral amino alcohol catalysts 5a and 5b have been proved to be effective for the enantioselective addition of diethylzinc to aldehydes, affording the corresponding sec-alcohols in moderate enantiomeric excesses with good to excellent yields. The recycled catalyst could be reused in the same reaction without significant deterioration in performance.


Assuntos
Aldeídos/química , Compostos Organometálicos/química , Polímeros/química , Catálise , Estrutura Molecular , Estereoisomerismo
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