98%
921
2 minutes
20
Mechanically interlocked polymers and molecules exhibit unique topological, physical, and chemical properties, making them highly promising for applications in molecular machines, molecular switches, artificial muscles, nano-actuators, nano-sensors, and biomedical technologies. While significant progress has been made in their synthesis and practical implementation, theoretical studies remain underexplored. In this work, we examine the role of entropic forces in daisy chain structures incorporating rotaxanes, with the ultimate goal of characterizing entropic nano-springs for use in nanomechanics and nanotechnology. Potential applications include artificial cytoskeletons, synthetic cells, and nano-mechanical logic gates.
Download full-text PDF |
Source |
---|---|
http://dx.doi.org/10.1063/5.0269708 | DOI Listing |
ACS Omega
September 2025
Aarhus University, Department of Chemistry, Langelandsgade 140, Aarhus DK 8000, Denmark.
Accurately modeling the binding free energies associated with molecular cluster formation is critical for understanding atmospheric new particle formation. Conventional quantum-chemistry methods, however, often struggle to describe thermodynamic contributions, particularly in systems exhibiting significant anharmonicity and configurational complexity. We employed umbrella sampling, an enhanced-sampling molecular dynamics technique, to compute Gibbs binding free energies for clusters formed from a diverse set of new particle formation precursors, including sulfuric acid, ammonia, dimethylamine, and water.
View Article and Find Full Text PDFJ Chem Phys
September 2025
Dipartimento di Fisica, Sapienza Università di Roma, P.le Aldo Moro 5, 00185 Rome, Italy.
Associative polymers (APs) with reversible, specific interactions between "sticker" sites exhibit a phase behavior that depends on a delicate balance between distinct contributions controlling the binding. For highly bonded systems, it is entropy that mostly determines whether, upon increasing concentration, the network forms progressively or via a first-order transition. With the aim of introducing an experimentally viable system tailored to test the subtle dependence of the phase behavior on binding site topology, we numerically investigate APs made of DNA, where "sticker" sites formed by short DNA sequences are interspersed in a flexible backbone of poly-T spacers.
View Article and Find Full Text PDFJ Phys Chem C Nanomater Interfaces
August 2025
Department of Chemical Engineering, University of Virginia, Charlottesville, Virginia 22903, United States.
Multiligand monolayers can self-organize into advantageous interfacial patterns that govern nanoparticle (NP) properties. Polyethylene glycol (PEG) is widely incorporated into self-assembled monolayers to enhance biocompatibility, particularly in drug delivery applications. Previous studies demonstrate that monolayer phase separation can be controlled by leveraging the energetic and entropic driving forces acting on ligands in the design of amphiphilic surfaces.
View Article and Find Full Text PDFJ Chem Phys
August 2025
Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, USA.
Low resolution coarse-grained (CG) models provide exceptional computational efficiency for simulating soft materials. Consequently, many studies employ CG models to determine free energy surfaces along order parameters or reaction coordinates of interest. However, because CG models average over atomic details, it is challenging to determine the energetic and entropic contributions to the resulting free energy surfaces.
View Article and Find Full Text PDFAcc Chem Res
September 2025
Department of Chemistry, Bowling Green State University, Bowling Green, Ohio 43403, United States.
ConspectusArtificial receptors for cations and anions utilizing noncovalent binding, transport, sequestration, or sensing in aqueous media must address enthalpic factors such as electrostatic attraction, hydrogen bonding, van der Waals forces, and London dispersion forces. The entropic component also significantly contributes to the free energy of association, especially in polar environments like water, where binding may be entropy-driven due to the release of ordered solvent molecules from the solvation sphere, increasing system entropy and resulting in a negative free Gibbs energy. Over the years, chemists have focused on enthalpic criteria, such as size complementarity and functional group interactions, for designing artificial receptors.
View Article and Find Full Text PDF