This article reviews recent advances in the development of reactive empirical force fields or potentials. In particular, we compare two widely used reactive potentials with variable-charge schemes that are desirable for multicomponent or multifunctional systems: the ReaxFF (reactive force field) and charge-optimized many-body (COMB) potentials. Several applications of these approaches in atomistic simulations that involve metal-based heterogeneous systems are also discussed.

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Peel-and-stick process, or water-assisted transfer printing (WTP), represents an emerging process for transferring fully fabricated thin-film electronic devices with high yield and fidelity from a SiO2/Si wafer to various non-Si based substrates, including papers, plastics and polymers. This study illustrates that the fundamental working principle of the peel-and-stick process is based on the water-assisted subcritical debonding, for which water reduces the critical adhesion energy of metal-SiO2 interface by 70 ~ 80%, leading to clean and high quality transfer of thin-film electronic devices. Water-assisted subcritical debonding is applicable for a range of metal-SiO2 interfaces, enabling the peel-and-stick process as a general and tunable method for fabricating flexible/transparent thin-film electronic devices.

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We have developed a ReaxFF reactive force-field description for bulk water and for proton transfer in the aqueous phase. This ReaxFF potential was parameterized exclusively against quantumchemical (QM) data, describing a broad range of intra- and intermolecular water interactions, including H–H, HO–OH and O=O bond dissociation energies, charge distributions, angle bending energies, binding energies for [H2O]2–35-clusters, H-transfer reactions pathways in H3O+/H2O, [H2O]n and HO−/H2O-clusters and ice densities and cohesive energies. We find good agreement between ReaxFF and QM for all these cases. We found that this QM-based ReaxFF potential gives a good description of bulk water phases and proton migration, reproducing experimental density, radial distribution and diffusion data, while it overestimates proton diffusion in the OH−/water system. We anticipate that this ReaxFF water description, in combination with ongoing ReaxFF-work on amines, carboxylic acids, phosphates and inorganic materials, should be highly suitable for simulating biochemical reactions involving enzymes and DNA. Furthermore, this potential can be used to simulate water reactions and proton diffusion on metal and metal oxide surfaces, opening up applications to catalysis, crystal growth and crack propagation studies. We have provided a specific example of this force field to heterogeneous catalysis, showing an oxygen/hydrogen recombination reaction in an iron nanoparticle.