Electrical Conductivity and In Situ SAXS Probing of Block Copolymer Nanocomposites Under Mechanical Stretching

Abstract

Elastomers based on block copolymers can self-organize into ordered nanoscale structures, making them attractive for use as flexible conductive nanocomposites. Understanding how ordered structures impact electrical properties is essential for practical applications. This study investigated the morphological evolution of flexible conductive elastomers based on polystyrene-b-poly(ethylene-co-butylene)-b-polystyrene (SEBS) block copolymers with aligned single- or multi-wall carbon nanotubes (SWCNTs or MWCNTs) and their electrical conductivity under large deformations. Oriented nanocomposites were obtained through injection molding and characterized using two different setups: tensile testing monitored by in situ small-angle X-ray scattering (SAXS) and tensile testing with simultaneous electrical conductivity measurements. Our findings demonstrate that structural orientation significantly influences electrical conductivity, with higher conductivity in the longitudinal direction due to the preferred orientation of carbon nanotubes. Tensile testing demonstrated that carbon nanotubes accelerate the process of realignment of the ordered structure. As a consequence, higher deformations reduced the conductivity of samples with longitudinal alignment due to the disruption of percolation contacts between nanotubes, while in samples with a transverse alignment the process promoted the formation of a new conductive network, increasing electrical conductivity.

Ensemble regression method for predicting the dependence of electrical resistance on the elongation of polymer composite materials

“…As a dataset we use Table 2. [27][28][29][30][31][32][33][34] The data processing and algorithm was implemented in the Python programming language.…”

“…As input data, as a rule, the electrical resistivity/conductivity, filler concentration, and composite composition are known, to control the relevance of results in training, we will use the results of experimental studies. [27][28][29][30][31][32][33][34] For the final testing of the results, we will use a test sample based on the experimental results, obtained in this work.…”

“…25,26 Thus, in the absence of orientation stretching, composite films PP/VGCF (polypropylene/vapor grown carbon fibers) with a filler concentration of 15% have a specific volumetric electrical resistance of 0.8 Ω Â m. During the orientation stretching by eight times, the electrical resistance increases by eight orders. 25 The question of the stretching influence on the electrically conductive properties of composite materials has been experimentally studied in many researches [27][28][29][30][31][32][33][34] (Table 2). The mechanical influences, namely stretching, on the electrically conductive properties of composite materials and microelectronic devices have been established.…”

EVA and SEBS-MA copolymers incorporated silicone rubber/SEBS blends: improvement of mechanical and thermal properties

“…Poly (styrene-ethylene butylene-styrene) triblock copolymer (SEBS) is one of the most important conventional thermoplastic elastomers (TPEs), which has good thermal stability, aging resistance, and electrical properties. Furthermore, weatherability resistance, good resistance to humidity and hydrolysis, and high elasticity are among the other properties of this copolymer that has made it find wide industrial applications 25 – 28 .…”