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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.

Resistance switching in metal-insulator-metal structures has been extensively studied in recent years for use as synaptic elements for neuromorphic computing and as nonvolatile memory elements. However, high switching power requirements, device variabilities, and considerable trade-offs between low operating voltages, high on/off ratios, and low leakage have limited their utility. In this work, we have addressed these issues by demonstrating the use of ultraporous dielectrics as a pathway for high-performance resistive memory devices. Using a modified atomic layer deposition based technique known as sequential infiltration synthesis, which was developed originally for improving polymer properties such as enhanced etch resistance of electron-beam resists and for the creation of films for filtration and oleophilic applications, we are able to create ∼15 nm thick ultraporous (pore size ∼5 nm) oxide dielectrics with up to 73% porosity as the medium for filament formation. We show, using the Ag/Al

The effect of non-idealities, namely pinhole defects and non-ideal lamellar stacking of nanosheets, on the performance of size-differentiated graphene oxide (GO) laminates is investigated using equilibrium molecular dynamics (MD) simulations. With the increase in sizes of the constituent GO nanosheets the water permeability of the layered GO membranes decreases and salt rejection increases. But with the inclusion of non-idealities the difference in water permeability between these membranes substantially reduced. The pinholes on the GO nanosheets provide shorter routes for trans-sheet flow, thereby increasing the water permeability of the membranes. The non-ideal stacking of the nanosheets without pinhole defects results in slight reduction in water permeability because of blockage of permeation pathways inside the membranes. However, with pinhole defects non-ideal stacking becomes favorable for water permeation through the layered GO membranes; as this time the non-ideal stacking leads to formation of voids inside the membranes, which act as routes for shorter permeation pathways. The effect of these non-idealities is more significant for layered GO membranes composed of large GO nanosheets. Although the water permeability through the layered GO membrane is greatly enhanced because of these non-idealities (about 10 times), the corresponding variation in the salt rejection is very low (