Effect of interfacial properties of filled carbon black nanoparticles on the conductivity of nanocomposite

Dielectric Constant Estimation of Spherical Particle-Filled Nanocomposites Based on the Poon and Shin Model, Considering Interphase Properties

A revised version of the Poon and Shin (PS) model, incorporating the effects of the interphase, is introduced to predict the dielectric permittivity of polymer nanocomposites reinforced with spherical nanoparticles. In this modified approach, both the spherical nanoparticle and its surrounding interphase region are treated as an equivalent nanoparticle, modeled as a core-shell structure. This assumption enables a more accurate representation of the composite, where the polymer matrix and the equivalent nanoparticles form a homogeneous mixture. The process of calculating the dielectric permittivity of the composite occurs in two distinct steps. Initially, the dielectric permittivity of the equivalent particle-comprising both the nanoparticle core and its interphase-is computed. Subsequently, the overall dielectric permittivity of the composite material is determined, considering the properties of the polymer substrate and the equivalent nanoparticles, all within the framework of the modified PS model. To verify the validity of the proposed model, experimental data are compared against the predicted values, showing a high level of agreement when the interphase characteristics are appropriately incorporated. Additionally, the influence of various factors, including the properties of the spherical nanoparticles, the interphase, and the polymer matrix, on the dielectric performance of the nanocomposite is thoroughly investigated. This enhanced PS model offers a valuable theoretical framework for designing polymer-spherical nanoparticle composites with superior dielectric properties, paving the way for their potential application in advanced electronic and energy storage devices.

A tortoise-inspired quadrupedal pneumatic soft robot that adapts to environments through shape change

Multi-terrain adaptation and landing capabilities pose substantial challenges for pneumatic bionic robots, particularly in crossing obstacles. This paper designs a turtle-inspired quadrupedal pneumatic soft crawling robot with four deformable bionic legs to mimic the structure and movement of turtle legs. Finite element software is used to design and optimize the wall thickness of the soft actuator. Experimental tests are conducted under different pressures to verify the bending capability of the upper leg (0-40 kPa) and lower leg (0-60 kPa). Four gait models of the robot are achieved by controlling the airflow in different chambers of four soft actuators. Then the corresponding test scenarios are established to confirm gait control effectiveness. The soft actuator is designed with adjusted gait overlap ratios (0, 0.25, 0.5, 0.75, 1), enabling the soft robot to overcome obstacles up to 25 mm in height, showcasing superior obstacle-crossing capabilities. In addition to moving straight (maximum speed: 0.41 BL s-1) and turning on rigid surfaces (45° s-1), the robot is capable of crawling on various complex terrains (cloth, sand, flat ground, and slope) as well as water planning. These characteristics make the robot suitable for a wide range of applications, such as search and rescue, exploration, and inspection. The robot's ability to traverse complex environments and its robust performance in various conditions highlight its potential for real-world deployment.