Multifunctionalization of carbon nanotube fibers with the aid of graphene wrapping
The excellent mechanical and electrical properties of carbon nanotubes is harnessed in a range of applications from advanced textiles through to supercapacitors, and artificial muscles. However, the mechanical properties of the CNT fiber can be affected by chemical modification of the CNTs, and the fabrication and performance depend strongly on the morphology of the fiber surface. In this hot paper Xiaohua Zhang, Qingwen Li and co-workers report a new method to modify the surface roughness and level of functionalization of CNT fibers, by wrapping them in graphene oxide or reduced graphene. The introduction of a graphene layer also has smoothing and shield effects, resulting in higher tensile strength and improved and stabilized performance. The nanotubes can also be further functionalised with polyaniline or TiO2 nanoparticles.
(J. Mater. Chem., 2012, 22, 16277-16282)
Microwave-assisted synthesis of ZnO–Y3Al5O12:Ce3+ composites with enhanced visible light photocatalysis
Light-converting materials such as up-converters and down-converters offer an intriguing route to improve the photocatalytic performance of hybrid photocatalysts. In this hot paper a team led by Likun Pan at East China Normal University report a one-step synthesis of ZnO–Y3Al5O12:Ce3+ composites using a microwave-assisted reaction of the ZnO precursor with a Y3Al5O12:Ce3+ suspension. The photocatalytic performance of the composites was found to be greatly improved compared with pure ZnO in the degradation of methylene blue under visible light irradiation. The team say that as far as they are aware this is the first report using the down-converting property of a phosphor in visible light photocatalysis. (J. Mater. Chem., 2012, 22, 16293-16298)
Dynamically bonded layer-by-layer films for self-regulated insulin release
Layer-by-layer assembled films using reversible or dynamic bonds are one option for the controlled and sustained release of drugs. In this hot paper a LbL film made from insulin–PVA and P(AAm–AAPBA) releases insulin at a rate that’s controlled by the environment. The rate of insulin release can be tuned by pH and ionic strength and importantly, it increases with increasing glucose concentration. (J. Mater. Chem., 2012, 22, 16299-16305)
Lanthanide-doped ultrasmall yttrium fluoride nanoparticles with enhanced multicolor upconversion photoluminescence
Ultrasmall upconversion nanoparticles with efficient multicolor photoluminescence are highly sought after for high contrast bioimaging; however, the nanocrystals should be smaller than 6 nm to ensure rapid clearance via the renal system whilst still maintaining efficient photoluminescence. In this hot paper Chunhui Yang, Gang Han and co-workers report a simple and reproducible thermolysis approach to synthesize 3.7 nm sized lanthanide-doped YF3 UC nanocrystals. Varying the concentration of the Yb3+ ions generates a range of colours and these ultrasmall nanoparticles was found to be about ten times brighter than that of 4.5 nm nanocrystals made of CaF2.
(J. Mater. Chem., 2012, DOI: 10.1039/C2JM32298F, Advance Article)