Effect of electron irradiation on few-layer boron nitride nanosheets/polydimethylsiloxane composite inspired pillar

Abstract Young’s modulus and friction force of the gecko-inspired materials are important parameters for the applications of climbing robots and devices. Increasing the friction force of polymer composite pillar with desirable Young’s modulus is current research focus to expand the potential applications of bio-inspired materials. Also, the stability of inspired pillar under radiated exposure is essential to be investigated to explore the irradiation effect on patterned composite array. Here the boron nitride nanosheets (BNNSs) have been exfoliated with assistance of hyperbranched polyethylene (HBPE) as polymer stabilizer via CH-π non-covalent interaction. The nanosheets were incorporated into polydimethylsiloxane (PDMS) mixture that was then utilized to prepare composite pillar via plasma etched silicon template. The electron irradiation was conducted to examine the morphology of patterned array and the mechanical property of PDMS composite. The coefficient of friction for PMDS composite decreases slightly after irradiation, and it retains high value around 1.2 for 0.2 wt% composite pillar with comparison to 1.3 for PDMS. The stress for irradiated PDMS decreases from 3.1 MPa to 1.8 MPa with the strain of 281% at accumulating dose of 5 × 1015 rad. During irradiation, the doubling terminating reaction is probably induced by the active radical sites in elastomer. The PDMS pillar exhibits large friction coefficient and high mechanical property due to new crosslinking network of elastomer during irradiation. This work develops polymer composite with pillar architecture by silicon template method, and sheds a light on the electron irradiation effect of composite pillar to pave the path for the application of gecko-inspired material in spacecraft.