Poly(ethyleneterephthalate) (PET) is a multi-purpose and widely used synthetic polymer in many industrial fields because of its remarkable advantages such as low cost, light weight, high toughness and resistance to chemicals, and high abrasion resistance. However, PET suffers from poor dyeability due to its non-polar nature, benzene ring structure as well as high crystallinity. In this study, PET fabrics were firstly treated with an alkaline solution to produce carboxylic acid functional groups on the surface of the PET fabric, and then was modified by polyelectrolyte polymer through the electrostatic layer-by-layer self-assembly technology. The polyelectrolyte multilayer-deposited PET fabric was characterized using scanning electron microscopy SEM, contact angle, Fourier transform infrared (FTIR) and X-ray photoelectron spectroscopy (XPS). The dyeability of PET fabrics before and after surface modification was systematically investigated. It showed that the dye-uptake of the polyelectrolyte multilayer-deposited PET fabric has been enhanced compared to that of the pristine PET fabric. In addition, its dyeability is strongly dependent on the surface property of the polyelectrolyte multilayer-deposited PET fabric and the properties of dyestuffs.

Stretchable and wearable opto-electronics have attracted worldwide attention due to their broad prospects in health monitoring and epidermal applications. Resistive strain sensors, as one of the most typical and important device, have been the subject of great improvements in sensitivity and stretchability. Nevertheless, it is hard to take both sensitivity and stretchability into consideration for practical applications. Herein, we demonstrated a simple strategy to construct a highly sensitive and stretchable graphene-based strain sensor. According to the strain distribution in the simulation result, highly sensitive planar graphene and highly stretchable crumpled graphene (CG) were rationally connected to effectively modulate the sensitivity and stretchability of the device. For the stretching mode, the device showed a gauge factor (GF) of 20.1 with 105% tensile strain. The sensitivity of the device was relatively high in this large working range, and the device could endure a maximum tensile strain of 135% with a GF of 337.8. In addition, in the bending mode, the device could work in outward and inward modes. This work introduced a novel and simple method with which to effectively monitor sensitivity and stretchability at the same time. More importantly, the method could be applied to other material categories to further improve the performance.

In this paper, gold/multi-walled carbon nanotube (Au/MWCNTs) composites were prepared via in situ reductions. The synthesized materials could effectively catalyze the system of square acid (SQA)-iron(II/III) to produce a significant color reaction. By designing the orthogonal test of three-factor and three-level, the three factors of sodium formate solution concentration, ultrasonic time and synthesis reaction time were optimized in the process of Au/MWCNTs preparation. Results showed that the Au/MWCNTs had the best catalytic activity under the conditions of sodium formate solution concentration of 400 mmol/L, ultrasonic for 30 min and reaction for 4 h. In a subsequent comparison with H₂O₂, it found that the catalytic performance of 1 mg of Au/MWCNTs composite was equivalent to that of H₂O₂ with the concentration of 0.28 mmol/L. It demonstrated that the prepared Au/MWCNTs composites had good catalytic activity, stable color and low background noise, indicating a good prospect in various fields including that of catalytic reaction, sensing analysis, and nanomaterials labeling.