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1. Single-molecule capture, release, and dynamical manipulation via reversible electrokinetic confinement (RECON)

   https://doi.org/10.1126/sciadv.adv8863  

   Pessôa, Matheus_A S; Jakuc, Piotr; Martins_e_Queiroz, Carolina; Duggan, Naomi; Liu, Ruiyao; Kautz, Seraphine; Ameur, Sarah; Liu, Zezhou; Dong, Wangwei; Ravikumar, Preethi; et al (September 2025, Science Advances)

   We present a nanofluidic device enabling single-molecule confinement through free-energy landscapes created by dynamic electrical gating of embedded nanoelectrodes. Unlike static geometric confinement, this system uses a parallel electrode configuration with nanoelectrodes placed in a dielectric layer. Localized electrokinetic fields at electrode wells form tunable attractive potential wells for bimolecular capture. By modulating the voltage bias waveform, the device allows precise control over confinement dynamics, enabling molecular capture, release, and exposure to periodic or stochastic confinement regimes. This flexibility facilitates the study of biomolecular behavior under dynamically adjustable conditions, including controlled confinement fluctuations. The device can manipulate diverse analytes such as double-stranded DNA, liposomes, and DNA nanotubes and facilitates introducing molecules into confined environments intact from bulk while providing enhanced tunability. With the ability to implement tailored confinement profiles, this platform represents a versatile tool for probing molecular confinement and behavior in complex, dynamically varying environments. 

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2. Differences in thermal expansion and motion ability for herringbone and face-to-face π-stacked solids

   https://doi.org/10.1107/S2052252521009593  

   Ding, Xiaodan; Zahid, Ethan; Unruh, Daniel K.; Hutchins, Kristin M. (January 2022, IUCrJ)

   A series of aromatic organic molecules functionalized with different halogen atoms (I/ Br), motion-capable groups (olefin, azo or imine) and molecular length were designed and synthesized. The molecules self-assemble in the solid state through halogen bonding and exhibit molecular packing sustained by either herringbone or face-to-face π-stacking, two common motifs in organic semiconductor molecules. Interestingly, dynamic pedal motion is only achieved in solids with herringbone packing. On average, solids with herringbone packing exhibit larger thermal expansion within the halogen-bonded sheets due to motion occurrence and molecular twisting, whereas molecules with face-to-face π-stacking do not undergo motion or twisting. Thermal expansion along the π-stacked direction is surprisingly similar, but slightly larger for the face-to-face π-stacked solids due to larger changes in π-stacking distances with temperature changes. The results speak to the importance of crystal packing and intermolecular interaction strength when designing aromatic-based solids for organic electronics applications. 

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3. Collective Vibrational Strong Coupling Effects on Molecular Vibrational Relaxation and Energy Transfer: Numerical Insights via Cavity Molecular Dynamics Simulations

   Li, T.E. Li; Nitzan, A.; Subotnik, J.E. (May 2021, Angewandte Chemie)

   null (Ed.)

   We use classical cavity molecular dynamics simulations to investigate the effect of optical cavity environment on vibrational energy transfer and relaxation. For a small fraction of vibrationally hot CO2 molecules immersed in a liquid-phase CO2 thermal bath, in a cavity that supports a cavity mode in resonance with the CO asymmetric stretch vibration, forming collective vibrational strong coupling (VSC) and a cavity mode accelerates hot molecule relaxation. This acceleration stems from the fact that polaritons can be transiently excited during the nonequilibrium process, which facilitates intermolecular vibrational energy transfer. The VSC effects on these rates (i) resonantly depend on the cavity mode detuning, (ii) cooperatively depend on Rabi splitting, and (iii) collectively scale with the number of hot molecules. This behavior weakens with increasing cavity size (at constant molecular density), that is, constant Rabi splitting) but remains meaningful up to cavities containing 10^4 molecules 

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4. pH swing cycle for CO ₂ capture electrochemically driven through proton-coupled electron transfer

   https://doi.org/10.1039/D0EE01834A  

   Jin, Shijian; Wu, Min; Gordon, Roy G.; Aziz, Michael J.; Kwabi, David G. (October 2020, Energy & Environmental Science)

   We perform a thermodynamic analysis of the energetic cost of CO 2 separation from flue gas (0.1 bar CO 2 (g)) and air (400 ppm CO 2 ) using a pH swing created by electrochemical redox reactions involving proton-coupled electron transfer from molecular species in aqueous electrolyte. In this scheme, electrochemical reduction of these molecules results in the formation of alkaline solution, into which CO 2 is absorbed; subsequent electrochemical oxidation of the reduced molecules results in the acidification of the solution, triggering the release of pure CO 2 gas. We examined the effect of buffering from the CO 2 –carbonate system on the solution pH during the cycle, and thereby on the open-circuit potential of an electrochemical cell in an idealized four-process CO 2 capture-release cycle. The minimum work input varies from 16 to 75 kJ mol CO2 −1 as throughput increases, for both flue gas and direct air capture, with the potential to go substantially lower if CO 2 capture or release is performed simultaneously with electrochemical reduction or oxidation. We discuss the properties required of molecules that would be suitable for such a cycle. We also demonstrate multiple experimental cycles of an electrochemical CO 2 capture and release system using 0.078 M sodium 3,3′-(phenazine-2,3-diylbis(oxy))bis(propane-1-sulfonate) as the proton carrier in an aqueous flow cell. CO 2 capture and release are both performed at 0.465 bar at a variety of current densities. When extrapolated to infinitesimal current density we obtain an experimental cycle work of 47.0 kJ mol CO2 −1 . This result suggests that, in the presence of a 0.465 bar/1.0 bar inlet/outlet pressure ratio, a 1.9 kJ mol CO2 −1 thermodynamic penalty should add to the measured value, yielding an energy cost of 48.9 kJ mol CO2 −1 in the low-current-density limit. This result is within a factor of two of the ideal cycle work of 34 kJ mol CO2 −1 for capturing at 0.465 bar and releasing at 1.0 bar. The ideal cycle work and experimental cycle work values are compared with those for other electrochemical and thermal CO 2 separation methods. 

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5. Thermal Transport in Poly(p-phenylene): Anomalous Dimensionality Dependence and Role of π–π Stacking

   https://doi.org/10.1021/acs.jpcb.3c02947  

   Yang, Cong; Raza, Saqlain; Li, Xiaobo; Liu, Jun (August 2023, The Journal of Physical Chemistry B)

   For heat conduction along polymer chains, a decrease in the axial thermal conductivity often occurs when the polymer structure changes from one-dimensional (1D) to three-dimensional (3D). For example, a single extended aliphatic chain (e.g., polyethylene or poly(dimethylsiloxane)) usually has a higher axial thermal conductivity than its double-chain or crystal counterparts because coupling between chains induces strong interchain anharmonic scatterings. Intuitively, for chains with an aromatic backbone, the even stronger π–π stacking, once formed between chains, should enhance thermal transport across chains and suppress the thermal conductivity along the chains. However, we show that this trend is the opposite in poly(p-phenylene) (PPP), a typical chain with an aromatic backbone. Using molecular dynamics simulations, we found that the axial thermal conductivity of PPP chains shows an anomalous dimensionality dependence where the thermal conductivity of double-chain and 3D crystal structures is higher than that of a 1D single chain. We analyzed the probability distribution of dihedral angles and found that π–π stacking between phenyl rings restricts the free rotation of phenyl rings and forms a long-range order along the chain, thus enhancing thermal transport along the chain direction. Though possessing a stronger bonding strength and stabilizing the multiple-chain structure, π–π stacking does not lead to a higher interchain thermal conductance between phenyl rings compared with that between aliphatic chains. Our simulation results on the effects of π–π stacking provide insights to engineer thermal transport in polymers at the molecular level. 

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