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Ionic liquids (ILs) are emerging as novel solvents that exhibit peculiar mechanical properties in the form of thin films on metal surfaces under normal pressure. However, the mechanical properties of ILs in the form of nano-meniscus have not been analyzed yet. Here, we investigate the shear viscoelasticity of a single IL meniscus at the nanoscale. To characterize the shear rheological properties of ILs, we employ a quartz tuning fork-based atomic force microscope, conduct dynamic force spectroscopy, and analyse shear properties using the non-Newtonian-Maxwell model. The elastic response of the IL nanomeniscus is found to be about 25 times higher than that of the bulk IL bridge, whereas the viscous responses are similar. In addition, by conducting shear velocity-dependent measurements, we find that the IL meniscus shows nonlinear rheological behaviours. Interestingly, we observe that the relaxation time of the IL increases at a tip-substrate distance of about 60 nm.
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http://dx.doi.org/10.1039/d0cp06003h | DOI Listing |
Biomacromolecules
September 2025
Division of Pharmacy and Optometry, Manchester Institute of Biotechnology, School of Health Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Oxford Road, M13 9PL Manchester, U.K.
This study investigates how hydrophobic and hydrophilic modifications at the C-terminus of the base peptide, KFEFEFKFK (KbpK), affect the hydrogel macroscopic properties. By the incorporation of phenylalanine (F, hydrophobic) and lysine (K, hydrophilic) residues, four variants, KbpK-K, KbpK-F, KbpK-KF, and KbpK-FK, were designed and evaluated. pH-concentration phase diagrams and Fourier transform infrared confirmed clear links showing how peptide hydrophobicity and charge influence β-sheet formation and macroscopic phase behavior.
View Article and Find Full Text PDFBiosystems
September 2025
Department of Physics, Lancaster University, Lancaster LA1 4YB, UK. Electronic address:
Swirling motion is an essential phenomenon that significantly influences numerous biological processes, such as the mixing of molecular components within living cells, nutrient transport, the structural changes of the cytoskeletons of contractile cells and the rearrangement of multicellular systems caused by collective cell migration. The dynamical relationship between subcellular and supracellular rearrangements enhances cell migration and contributes to tissue homeostasis. However, the basic mechanisms that drive swirling motion in biological contexts remain a matter of ongoing inquiry.
View Article and Find Full Text PDFJ Phys Condens Matter
September 2025
Department of Physics, Universidade Federal de Vicosa, Av. P. H. Rolds, s/n, Vicosa, Vicosa, 36570-000, BRAZIL.
Recent works indicate that heterogeneous response and non-Markovianity may yield recognizable hallmarks in the microrheology of semisolid viscoelastic materials. Here we perform numerical simulations using a non-Markovian overdamped Langevin approach to explore how the microrheology experienced by probe particles immersed in an effective semisolid material can be influenced by its micro-heterogeneities. Our results show that, besides affecting the mean squared displacement, the time-dependent diffusion coefficient, and the shear moduli, the micro-heterogeneities lead to displacement distributions that deviate from the usual Gaussian behavior.
View Article and Find Full Text PDFJ Chem Phys
September 2025
Fakultät Physik, Technische Universität Dortmund, D-44221 Dortmund, Germany.
The dynamics of the different constituents of the ionic liquid 1-hexyl-3-methylimidazolium chloride (HmimCl) is investigated using nuclear magnetic resonance including chlorine relaxometry, line shape analysis, and proton-detected diffusometry, as well as frequency-dependent shear mechanical measurements. This combination of techniques is useful to probe the individual motions of the anions and the cations, and the sample's overall flow response. The 35Cl- dynamics appears to be close to the structural (or α-) relaxation as seen by rheology.
View Article and Find Full Text PDFBiomed Eng Lett
September 2025
Department of Mechanical Engineering, University of Nevada, Las Vegas, Las Vegas, NV 89154 USA.
Alginate is known to readily aggregate and form a physical gel when exposed to cations, making it a promising material for bioprinting applications. Alginate and its derivatives exhibit viscoelastic behavior due to the combination of solid and fluid components, necessitating the characterization of both elastic and viscous properties. However, a comprehensive investigation into the time-dependent viscoelastic properties of alginate hydrogels specifically optimized for bioprinting is still lacking.
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