Search

With the rapid development of smart wearable devices and the urgent demands for new energy resources, fibrous flexible power supply units had attracted a lot of interest. Here, we reported the fabrication of polylactic acid (PLA) piezoelectric nanofibrous yarn-based fabric through conjugated electrospinning and weaving process. Five kinds of PLA yarns including poly(l-lactide) (PLLA), poly(d-lactide) (PDLA), PLLA positive/PDLA negative, PDLA positive/PLLA negative, and PLLA/PDLA mixture (1:1 w/w) ones were prepared and investigated. Among these, the PLLA/PDLA yarn had more uniform and oriented structure with 301 MPa tensile strength, which could meet the requirement of weaving. A 4 cm × 4 cm woven PLLA/PDLA fabric could provide a maximum current of 90.86 nA and a voltage of 8.69 V under 5 N force, and the piezoelectricity could be enhanced by the fabric area and the applied force. This approach may be helpful for the design of wearing generators.

In order to make cotton spunlaced nonwoven keeping well air permeability and a certain waterrepellent effect at the same, atmospheric pressure plasma technology was adopted. Hexamethyldisiloxane was used as monomer for the study of cotton spunlaced nonwoven single water-repellent modification experiment. After modification, hydrophobic surface layer was formed on the surface of nonwoven sample. water-repellent theory of modified nonwoven surface was analyzed combining with lotus effect. Infrared spectroscopy test results showed that hydrophobic groups like Si--CH3, Si--C and so on were generated on the modified surface. Water contact angle of the modified nonwoven was tested and it could be reached 157° on the treated surface in maximum. The surface without treatment were infiltrated and showed excellent single water-repellent effect. When modified nonwoven sample was treated by friction and placed for different time, the water contact angle was not changed too much. The water-repellent property of modified nonwoven was stable. It is considered that cotton spunlaced nonwoven after modified by atmospheric pressure plasma technology with hexamethyldisiloxane as monomer has excellent single water-repellent property. [ABSTRACT FROM AUTHOR]

Flexible/stretchable strain sensors have attracted much attention due to their advantages for human-computer interaction, smart wearable and human monitoring. However, there are still great challenges on gaining super durability, quick response, and wide sensing range. This paper provides a simple process to obtain a sensor which is based on graphene (GR)/carbon nanotubes (CNTs) and Ecoflex hybrid, which demonstrates superb endurance (over 1000 cycles at 100% strain), remarkable sensitivity (strain over 125% sensitivity up to 20) and wide sensing range (175%). All results indicate that it is capable for human movement monitoring, such as finger and knee bending and pulse beat. Most importantly, it can be used as a warning function for the night cyclist's ride. This research provides the feasibility of using this sensor for practical applications. A stretchable strain sensor takes GR and CNTs as conductive fillers and takes Ecoflex as the substrate through simple ultrasonically mixture and coating process. It can easily match human movement to complete finger and knee bending, pulse beat and breathing monitoring. Furthermore, the application of safety warning for bicycle riders at night has been successfully realized. [ABSTRACT FROM AUTHOR]