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We introduce a multi-reward reinforcement learning (RL) approach to train a flexible bond-order potential (BOP) for 2D phosphorene based on ab initio training data sets. Our approach is based on a continuous action space Monte Carlo tree search algorithm that is general and scalable and presents an efficient multiobjective optimization scheme for high-dimensional materials design problems. As a proof-of-concept, we deploy this scheme to parametrize multiple structural and dynamical properties of 2D phosphorene polymorphs. Our RL-trained BOP model adequately captures the structure, energetics, transformation barriers, equation of state, elastic constants, and phonon dispersions of various 2D P polymorphs. We use this model to probe the impact of temperature and strain rate on the phase transition from black (α-P) to blue phosphorene (β-P) through molecular dynamics simulations. A decrease in critical strain for this phase transition with increase in temperature is observed, and the underlying atomistic mechanisms are discussed.

The impact of grapefruit seed extract (GFSE) as an antibacterial agent on citric acid (CA) crosslinked sodium carboxymethylcellulose (NaCMC)/hydroxypropylmethylcellulose (HPMC) hydrogel films has been studied by incorporating different quantities of GFSE. The prepared films were examined for their physical, thermal, mechanical and antibacterial properties. It was observed that crystallinity and initial decomposition temperature of hydrogel films decreased with GFSE concentration. Furthermore, the swelling degree and tensile strength of hydrogel films were found to be 257.29 ± 5.08%–162.06 ± 1.78% and 11.61 ± 0.27–2.21 ± 0.94 MPa for increasing GFSE concentration varying from 0.25% - 1.5% (v/v). The presence of nanoparticles in the films was observed by FESEM and FETEM analysis. It was confirmed that the formation of nanoparticles (micelles) is due to the addition of NaCMC and GFSE, probably glycerides, which is one of the main components in GFSE. The hydrogel films have demonstrated excellent antimicrobial activity and elongation at break (%). Moreover, zeta potential of nanoparticles was recorded to be −55.26 mV ascertaining their stability in water that contributed to a higher antimicrobial activity against gram negative bacteria. All these outcomes prove the nanocomposite films to be a potential substitute for hydrogels loaded with synthetic drugs in wound healing and other biological applications.