Ultrastrong, Free-Standing and Large Nanofilms of Pyrenearamid

We introduce poly(1,6-pyrene terephthalamide) polymer (PPyrTA) as an aromatic polyamide analogue of poly(p-phenylene terephthalamide) (PPTA), also known as Kevlar®. This work shows that the incorporation of polycyclic aromatic pyrene moieties improves drastically the mechanical properties of the polymeric structure, increasing elastic nanoindentation-determined modulus and hardness by factors of 1.9 and 4.3, respectively. Liquid deprotonated dispersions of PPyrTA nanofibers were used as nanoscale building block for producing large-surface, free-standing polymer macroscopic nanofilms. This 2D assembly leads to further significant improvements in reduced modulus and hardness (more than twice) compared to the starting polymer macroscale fibres, due to a better re-organizational arrangement of the PPyrTA nanofibers in the nanofilms, formed under 2D spatial confinement.

Ultrastrong, Free-Standing and Large Nanofilms of Pyrenearamid

We introduce poly(1,6-pyrene terephthalamide) polymer (PPyrTA) as an aromatic polyamide analogue of poly(p-phenylene terephthalamide) (PPTA), also known as Kevlar®. This work shows that the incorporation of polycyclic aromatic pyrene moieties improves drastically the mechanical properties of the polymeric structure, increasing elastic nanoindentation-determined modulus and hardness by factors of 1.9 and 4.3, respectively. Liquid deprotonated dispersions of PPyrTA nanofibers were used as nanoscale building block for producing large-surface, free-standing polymer macroscopic nanofilms. This 2D assembly leads to further significant improvements in reduced modulus and hardness (more than twice) compared to the starting polymer macroscale fibres, due to a better re-organizational arrangement of the PPyrTA nanofibers in the nanofilms, formed under 2D spatial confinement.

NiSi Nanowires and Nanobridges Formed by Metal-Induced Growth

Nickel monosilicide (NiSi) nanowires (NWs) were fabricated by metal-induced growth at 575 °C. The solid-state reaction of Ni and Si provides linear grown NWs. The parallel grown NW forms a nanobridge (NB) across a trench, patterned with a simple optical lithography and metal lift-off method. The Ni pads gave a good Ohmic contact without affecting the I-V transport characteristics through a NB. The metallic NB, 2.73 µm in length and 50 nm in diameter, gave a low resistance of 148 . The self-assembled nanobridge can be applied to form nanocontacts at relatively low temperatures. The MIG NB is a promising 1 dimensional nanoscale building block to satisfy the need of ‘self and direct’ assembled ‘bottom-up’ fabrication concepts.