Over the last twenty years, scientists have developed many techniques to synthesize polymeric nanoparticles for a wide range of applications including surface coating, sensor technology, catalysis, and nanomedicine. However, the precise control of the size and shape of polymer nanoparticles remains challenging, and RDRP techniques still fall well short of producing large, well-defined macromolecules with the same size and degree of precision as nature (proteins, nucleic acids, etc.). In new work, researchers have developed a new technique to precisely control the size and shape of polymeric nanoparticles.
The most common method for making nanofibers employs electrospinning that uses an electrical charge to draw nanofibers from a polymeric solution. This technique utilizes large voltages and is strongly influenced by the dielectric properties of the material. It is also impossible to electrospin many biopolymers without blending with another polymer. Addressing these drawbacks, a team of researchers report a new method - magnetospinning - which utilizes a simple set-up that is independent of the dielectric constant of the solvent and polymer used.
From a 3D printing perspective, graphene has been previously incorporated into 3D printed materials, but most of these constructs comprise no greater than about 20 volume % of the total solid of the composite, resulting in electrical properties that are significantly less than what has been achieced in new work. Here, researchers show that high volume fraction graphene composite constructs can be formed from an easily extrudable liquid ink into multi-centimeter scaled objects.
Supramolecular chemistry deals with molecular building-blocks that interact with each other in a dynamic manner, similar to what is seen in nature. Taking advantage of this, several 'smart' materials have been developed for biomedical applications by careful design of these building-blocks. These materials have especially interesting properties like self-healing and responsiveness to light and electricity. Researchers have now explored the possibility of developing a bacterial strain with the ability to interact dynamically with a popular supramolecular building-block.
Energy-scavenging fabrics based on nano-sized generators that have piezoelectric properties could eventually lead to wearable 'smart' clothes that can power integrated electronics and sensors through ordinary body movements. Researchers have now demonstrated a new type of fully flexible, very robust and wearable triboelectric nanogenerator with high power-generating performance and mechanical robustness. This was achieved by applying a bottom-up nanostructuring approach where a silver-coated textile and polydimethylsiloxane (PDMS) nanopatterns based on ZnO nanorod arrays were used as active triboelectric materials.
Existing fabrication techniques for 3D microstructures usually suffer from complicated equipment, time-consuming processes, and insufficient controllability on precise structures. Constructing controllable 3D self-assembly microstructure in a simple and convenient way is still a challenge. In new work, researchers propose a facile strategy to directly assemble nanoparticles into controllable 3D structures from one microdroplet based on 0D hydrophilic pinning pattern.
The successful implementation of graphene-based devices invariably requires the precise patterning of graphene sheets at both the micrometer and nanometer scale. It appears that 3D-printing techniques are an attractive fabrication route towards three-dimensional graphene structures. Researchers have now used flakes of chemically modified graphene, namely graphene oxide GO and its reduced form rGO, together with very small amounts of a responsive polymer, to formulate water based ink or pastes to be used in 3D printers.
Designing systems that build themselves is one of the great dreams of nanotechnology researchers, and they are taking great strides towards developing such 'bottom-up' nanotechnology fabrication techniques. Fabrication processes based on DNA might change this: DNA origami have been heralded as a potential breakthrough for the creation of nanoscale devices. Researchers have now developed methods to assemble DNA-functionalized microparticles into a colloidal gel, and to extrude this gel with a 3D printer at centimeter size scales.