W. Thongsuwan

Stretchable and flexible high-strain sensors made using carbon nanotubes and graphite films on natural rubber.

Conventional metallic strain sensors are flexible, but they can sustain maximum strains of only ∼5%, so there is a need for sensors that can bear high strains for multifunctional applications. In this study, we report stretchable and flexible high-strain sensors that consist of entangled and randomly distributed multiwall carbon nanotubes or graphite flakes on a natural rubber substrate. Carbon nanotubes/graphite flakes were sandwiched in natural rubber to produce these high-strain sensors. Using field emission scanning electron microscopy, the morphology of the films for both the carbon nanotube and graphite sensors were assessed under different strain conditions (0% and 400% strain). As the strain was increased, the films fractured, resulting in an increase in the electrical resistance of the sensor; this change was reversible. Strains of up to 246% (graphite sensor) and 620% (carbon nanotube sensor) were measured; these values are respectively ∼50 and ∼120 times greater than those of conventional metallic strain sensors.

Highly stretchable and sensitive strain sensors using nano-graphene coated natural rubber

ABSTRACT Flexible, stretchable and wearable sensors are needed for the human motion detection. Here, a highly stretchable and sensitive strain sensor is fabricated based on the coating of nano-graphene platelets on natural rubber by simple dry coating process. The gauge factors are adjustable in the ranges of 0.78–52.53 depended on the preparation conditions and strain state. The sensors showed a high stretchability up to 750% and high durability of 1500 stretching–releasing cycles. The stretchable strain sensors are capable of detecting a bending fingers and the pulse of radial artery on the wrist. In addition, a smart glove made form five independent strain sensors was created. The data of the glove finger motions are used to control an avatar robotic hand.

Preparation of Iron Oxide Nanoparticles by a Pyrosol Technique

Iron oxide nanoparticles were prepared from an iron nitrate solution by a pyrosol technique. The precursor solution was atomized by a mist generator in order to form an aerosol which was brought into a tube furnace by a controlled flowing air stream. The pyrolysis of the aerosol was occurred to form the particles inside the furnace at 350 °C. Scanning electron microscopy images have shown that a mean diameter of the particles is in good agreement with the third root of the precursor concentration. X-ray diffraction patterns have revealed that the main peaks from the samples are corresponding to the α-Fe2O3 phase.