So far, it has been generally accepted knowledge that boron nitride nanotubes (BNNTs) are highly inert to oxidative treatments and can only be covalently modified by highly reactive species. By contrast, oxidation of carbon nanotubes has been proven very convenient and fundamentally important to modify the nanotube structure and morphology via controlled corrosive effects. Now, researchers have discovered a convenient method to disperse and chemically modify the morphology of BNNTs by sonication in aqueous ammonia solutions.
Researchers have now shown that, by varying the shape of magnetite nanoparticles, they can control the nature of the self-assembled structures as the nanoparticles assemble. This new work provides guidelines for the design of new self-assembled materials. Self-assembly of nanoparticles driven by competing forces can result in truly unique structures, the diversity and complexity of which could be particularly striking if the building blocks were simultaneously coupled by short- and long-range forces of different symmetries.
Conjugated polymer based organic photovoltaic (OPV) devices have been the subject of increasing research interest over the past years due to their potential of being light weight, mechanically flexible, semitransparent. To increase the efficiency of OPV, it is necessary to achieve a precisely controlled donor-acceptor phase separation within the short exciton diffusion length without dead ends, as well as a high hole mobility within the polymer. Now, researchers have demonstrated the effects of nanostructure geometry on the nanoimprint induced P3HT chain alignment and the performance of nanoimprinted photovoltaic devices.
Industrial production processes, by and large, rely on robotic assembly lines that place, package, and connect a variety of disparate components. While the manufacturing world is dominated by robots, there are applications where the established processes of serial 'pick and place' and manipulation of single objects reach scaling limits in terms of throughput, alignment precision, and the minimal component dimension they can handle effectively. By contrast, the emerging methods of engineered self-assembly are massively parallel and have the potential to overcome these scaling limitations.
Many nanofabrication techniques depend on creating a structure on one substrate and then transferring it via various processes onto another, desired, substrate. Often, these methods are not generally applicable as they suffer from the process-specific drawbacks, such as for instance intolerance of transferred nanostructures to chemical etchant, and the harsh thermal environment needed. A novel universal and rapid method allows transferring nanostructures with various dimensions onto diverse substrates with high fidelity.
Thermoelectric materials hold great promise for turning waste heat back into useful power and are touted for use in hybrid cars, new and efficient refrigerators, and other cooling or heating applications. But they have one big drawback: they are very inefficient. Since thermoelectric devices work by maintaining a temperature difference between their different sides, it is important that the used materials have low conductivity, i.e. are good thermal insulators.
The microstructures of carbon nanotube assemblies determine their properties, for example, highly graphitized CNTs exhibit excellent mechanical and electrical properties; while CNTs with defects and poor crystallinity are beneficial for research on field emission property and hydrogen storage capacity. Therefore, it is of vital importance to control the CNT microstructures effectively for desired applications. A new technique can solve a problem of three-dimensional orientation control of CNTs in microscopic scale.
There are a wide range of passive devices such as beads, wells and tubes that can be used to capture and confine single cells. Previous active cell grippers with moving parts have relied on electrical modalities which can be challenging to implement off-chip and in a highly parallel manner. Researchers have now, for the first time, demonstrated an untethered active microgripper that can be used to capture and contain single cells.