Superhydrophobic Alkanethiol-Coated Microsubmarines for Effective Removal of Oil

We demonstrate the use of artificial nanomachines for effective interaction, capture, transport, and removal of oil droplets. The simple nanomachine-enabled oil collection method is based on modifying microtube engines with a superhydrophobic layer able to adsorb oil by means of its strong adhesion to a long chain of self-assembled monolayers (SAMs) of alkanethiols created on the rough gold outer surface of the device. The resultant SAM-coated Au/Ni/PEDOT/Pt microsubmarine displays continuous interaction with large oil droplets and is capable of loading and transporting multiple small oil droplets. The influence of the alkanethiol chain length, polarity, and head functional group and hence of the surface hydrophobicity upon the oil–nanomotor interaction and the propulsion is examined. No such oil–motor interactions were observed in control experiments involving both unmodified microengines and microengines coated with SAM layers containing a polar terminal group. These results demonstrate that such SAM-Au/Ni/PEDOT/Pt micromachines can be useful for a facile, rapid, and efficient collection of oils in water samples, which can be potentially exploited for other water–oil separation systems. The integration of oil-sorption properties into self-propelled microengines holds great promise for the remediation of oil-contaminated water samples and for the isolation of other hydrophobic targets, such as drugs

Striped Alloy Nanowire Optical Reflectance Barcodes Prepared from a Single Plating Solution

The preparation of multisegment alloy nanowire barcodes with optical-reflectance striping patterns and large coding capacity using a template-assisted electro-deposition from a single gold-silver plating solution, was presented. A template-assisted electro-deposition method can be applied in a predetermined order for different duration for producing alloy segment of controlled length. The nanowire was prepared from an 85/15 (v/v) Au/Ag plating solution by applying different potentials. Barcodes were prepared by varying the deposition conditions, while using the same plating solution. The multipotential templated deposition from plating solution resulted in distinct stepwise variation of the alloy composition along the length of the nanowires. The reflectance intensity of barcodes was determined using the highest intensity value corresponding to a prevalently silver segment deposited at -0.50 V