@article{jani_farias_jain_houston_velev_santiso_hsiao_khan_2024, title={Isothermal Titration Calorimetry Reveals Entropy-Driven Bisphenol A Epoxy Resin Adhesion to Metal Oxide Surfaces}, volume={1}, ISSN={["1520-5835"]}, url={https://doi.org/10.1021/acs.macromol.3c02440}, DOI={10.1021/acs.macromol.3c02440}, abstractNote={Polymer-coated metals are ubiquitous in multiple industries as a corrosion protection strategy. Particularly in food and beverage packaging, bisphenol A (BPA)-based epoxy coatings provide an excellent barrier and strong adhesion to metals. There is, however, a need to design safer, alternative coatings with similar adhesion as BPA-epoxies due to environmental and health concerns associated with BPA. Limited critical information exists on epoxy-metal interactions and the effect of interfacial functional group concentration on overall adhesion due to the constraints of most experimental methods, which typically probe the interface only within a few nanometers in situ. Herein, we use isothermal titration calorimetry (ITC) and molecular dynamics simulations to characterize the thermodynamics of epoxy-metal oxide binding in the liquid phase and identify the influence of epoxy resin structure and metal oxide surface chemistry in dictating the binding process. Across a series of epoxy resins and three metal oxides, we reveal a previously unreported dominant role of entropy in the binding process, primarily facilitated by the release of bound solvent molecules from the epoxy/metal interface with possible contributions from dispersive OH–π interactions between the benzene rings of the resin and the –OH groups on the metal oxide surface. Enthalpy-favored hydrogen bonding between the –OH groups of the resin and the metal oxide plays a supporting role in the binding, with its participation dependent on the interfacial –OH group concentration. ITC therefore offers key molecular insights into the relative functional group contributions to the adhesion mechanism and informs the rational design of next-generation polymer coatings.}, journal={MACROMOLECULES}, author={Jani, Pallav K. and Farias, Barbara V. and Jain, Rakshit Kumar and Houston, Katelyn R. and Velev, Orlin D. and Santiso, Erik E. and Hsiao, Lilian C. and Khan, Saad A.}, year={2024}, month={Jan} }
 @article{jain_hall_santiso_2023, title={Using Enhanced Sampling Simulations to Study the Conformational Space of Chiral Aromatic Peptoid Monomers}, volume={19}, ISSN={["1549-9626"]}, DOI={10.1021/acs.jctc.3c00803}, abstractNote={Peptoids, or N-substituted glycines, are peptide-like materials that form a wide variety of secondary structures owing to their enhanced flexibility and a diverse collection of possible side chains. Compared to that of peptides, peptoids have a substantially more complex conformational landscape. This is mainly due to the ability of the peptoid amide bond to exist in both cis- and trans-conformations. This makes conventional molecular dynamics simulations and even some enhanced sampling approaches unable to sample the complete energy landscapes. In this article, we present an extension to the CGenFF-NTOID peptoid atomistic forcefield by adding parameters for four side chains to the previously available collection. We employ explicit solvent well-tempered metadynamics simulations to optimize our forcefield parameters and parallel bias metadynamics to study the cis-trans isomerism for SN1-phenylethyl (s1pe) and SN1-naphthylethyl (s1ne) peptoid monomers, the free energy minima generated from which are validated with available experimental data. In the absence of experimental data, we supported our atomistic simulations with ab initio calculations. This work represents an important step toward the computational design of peptoid-based materials.}, number={24}, journal={JOURNAL OF CHEMICAL THEORY AND COMPUTATION}, author={Jain, Rakshit Kumar and Hall, Carol K. and Santiso, Erik E.}, year={2023}, month={Nov}, pages={9457–9467} }
 @article{perez-mas_martin-molina_jain_quesada-perez_2019, title={Effect of dispersion forces on the behavior of thermosensitive nanogels: A coarse-grained simulation study}, volume={288}, ISSN={["1873-3166"]}, DOI={10.1016/j.molliq.2019.111101}, abstractNote={The main goal of this work is to evaluate the effect of dispersion forces on different properties of nanogels, such as size, net charge and surface electrostatic potential. This task was done by means of Monte Carlo coarse-grained simulations of nanogels in the presence of three different electrolytes. This model allows us to explicitly consider the dispersion interactions between ions inside the nanogel and monomer units rather than interactions between the ions and the nanoparticle as a whole. Our simulations reveal that dispersion forces can be responsible for charge inversion and the surface electrostatic potential inversion that cationic nanogels undergo in the presence of NaSCN. Moreover, these phenomena only take place if the bare charge of the nanogel is small enough. Our results also suggest that dispersions forces can induce a high capacity of permeation of some ions, such as thiocyanate, even into collapsed nanogels.}, journal={JOURNAL OF MOLECULAR LIQUIDS}, author={Perez-Mas, Luis and Martin-Molina, Alberto and Jain, Rakshit Kumar and Quesada-Perez, Manuel}, year={2019}, month={Aug} }