Jayati Sarkar

This aim of this study is to investigate the structure-property-function relationship of PBAT/PHBV blends by comparing rapid spin coating and porogen-assisted solvent casting. Spin coating induces “kinetic trapping”, creating fully amorphous 2D films. Conversely, solvent casting allows PHBV crystallization, forming semicrystalline 3D porous scaffolds. While both 50:50 blends exhibit cocontinuous morphologies, they remain structurally distinct. Despite similar chemistries, spin-coated films show enhanced hydrophilicity due to high nanoscale roughness (Wenzel model). Biological evaluations confirm that both systems are noncytotoxic. Notably, spin-coated films, particularly the 50:50 blend, exhibit enhanced in vitro biocompatibility and rapid initial proliferation. However, their 2D nature eventually leads to contact inhibition. In contrast, the 3D porous 50:50 solvent-cast scaffold supports logarithmic proliferation, yielding a ∼160% increase in ALP activity and 228% higher terminal mineralization. Ultimately, while the 50:50 spin-coated blend serves as a resource-efficient, bioactive surface coating, the 50:50 solvent-cast scaffold provides the optimal 3D biomimetic niche for bone tissue engineering.

Context Polymer nanocomposites gain functionality from nanoscale fillers, yet the magnitude of structural and transport changes imparted by an isolated graphene sheet to dilute atactic polystyrene (aPS) chains in a good solvent remains unclear. We probe how chain dimensions, conformational statistics, cohesive energy density, and diffusivity respond to graphene when the matrix is dominated by toluene, a processing-relevant solvent. The results provide quantitative guidance for the rational design of dilute polymer nanocomposites in which graphene predominantly modulates the local structure without significantly altering the global chain statistics. Methods All-atom molecular dynamics simulations with the COMPASS II force field were performed for aPS oligomers containing 30 and 50 repeat units at 298 K. Each system (1, 3, or 5 chains) was equilibrated and sampled for 10 ns with 2 fs timestep in Materials Studio, both with and without a 2.46 nm graphene sheet. Ensemble analyses covered end-to-end distances, radii of gyration, probability densities, mean-squared displacements, diffusivities, cohesive energy density, and interaction-energy traces, providing statistically converged comparisons across compositions.

This paper offers a reliable methodology to calculate HOMO‐LUMO energy gaps in furan‐fused helicenes ([n]FH) by employing 16 DFT functionals (B3LYP, B3LYP‐D, B3LYP‐D3, B3LYP‐D3BJ, CAM‐B3LYP, LC‐BLYP, HSE06, LC‐ωPBE, M06, MN15, PBE0, PBe0DH, ωB97XD, B2PLYP, B2PLYP‐D3, and B2PLYP‐D3BJ). The fundamental gaps (Δ E _CCSD(T) = IE − EA) are used as reference values for a reliable benchmark for energy gaps for oxa[n]helicenes ([n]FH, n = 1–4). [n]FH yields blue‐shifted HOMO‐LUMO gaps relative to sulfur‐, selenium‐, and tellurium‐based analogues. A dimerization study reveals that oxa[n]helicenes are very resistant to dimerization in DCM solvent in neutral as well as cationic states. MD simulations using the COMPASSIII force field in DCM solvent demonstrate that oxa[n]helicenes are highly resistant to dimerization in cationic states in the presence of counter ions. Optimally tuned ω values for LC‐ωPBE, LC‐BLYP, and ωB97XD in DCM (SMD solvation model) are almost ~20 to 100 times less than those in the gas phase, with the HOMO‐LUMO gaps in solvent much smaller. In addition, PBC‐DFT calculations reveal that the band gap obtained at PBC‐PBE0 and PBC‐B3LYP levels is quite comparable to the energy gap obtained at optimally tuned ω values for LC‐ωPBE, LC‐BLYP, and ωB97XD in DCM solvent. HOMO‐LSOMO gaps of oxa[n]helicene radical cations also blueshift compared to their S‐, Se‐, and Te‐based counterparts. TDDFT calculation with CAM‐B3LYP functional shows intense infrared absorption in furan‐based helicene radical cations, reflecting optoelectronic potential. This research emphasizes that the accuracy in excited‐state properties can be achieved with optimally tuned LC‐ωPBE, LC‐BLYP, and ωB97XD functionals, which are quite comparable to results obtained with the CAM‐B3LYP functional for neutral and radical cations of oxa[n]helicenes. These radical cation systems showed comparable absorption in the infrared range like S‐systems. Overall, our benchmarking studies lead to better predictions of HOMO‐LUMO gaps of oxa[n]helicenes. This work offers the much‐needed insights into the design of furan‐based helicene, opening doors to future advanced organic materials for electronics and photonics technology.

Morphological phase separation (M P S) of the thin liquid film is a complex interplay of intermolecular forces, hydrodynamic instability, and fluid properties. This study investigates the influence of thickness-dependent viscosity (liquid film viscosity decreases with an increase in film thickness) on the morphological phase separation in thin liquid film by incorporating inhomogeneous rheology. Based on the continuum hydrodynamic model with non linearly dependent viscosity function of local thickness, we numerically simulate the pattern formation dynamics over a broad time range. Our results show that the early and late phase separation stages conform to classical spinodal behaviour but the intermediate phase separation stage exhibits sub-spinodal behaviour due to rheological inhomogeneity. The intermediate phase separation stage reveals the emergence of sub-spinodal lengthscales through the formation of satellite defects between already growing primary defects if the mobility in thinner regions is very low. It also highlights trimodal defect height distribution, in contrast to the generally observed bimodal distributions in homogeneous viscosity films.

This paper primarily focuses on areas within non-Newtonian fluid mechanics that remain underexplored or inadequately investigated. It highlights research domains that have not received sufficient attention or detailed study, while also considering the emergence of new areas unexplored by recent scientific and technological advancements. For example, this study explores research directions and innovative modeling and theoretical strategies for understanding fluid dynamics in complex, deformable, and branched flow systems across multiple scales. The elastoviscoplastic behavior of fluids under external forcing is used to model droplet spreading, coalescence, and filtering over porous and soft substrates. Wall slip and junction resistance effects of the flow are in a tree-like structure. The study also highlights and explores research directions in the flow physics of non-Newtonian fluids that exhibit odd viscosity and odd elasticity, focusing on their unconventional stress–strain responses and the resulting unique flow behaviors. The objective of this paper is to raise awareness about these relatively neglected or unexplored areas of research, encouraging researchers to put efforts toward these promising domains. By doing so, they can contribute to advancing the field in ways that diverge from which have already been sufficiently explored and may lead to breakthroughs and novel discoveries by generalizing the existing laws or creating new models and laws. Moreover, addressing these under-explored areas could have far-reaching implications for both theoretical and practical applications in non-Newtonian fluid mechanics. Investigating these areas more deeply could uncover new insights, enhance existing models, and drive forward technological advancements that were previously overlooked. In addition, this paper will briefly discuss the potential introduction of novel tools, techniques, and methodologies that could be applied to these research areas, as well as to the broader field of non-Newtonian fluid mechanics. Furthermore, we also discuss the current and upcoming applications using non-Newtonian fluids. These innovations could open up new avenues of exploration and help overcome some of the existing limitations in past and current research.

This paper primarily focuses on areas within non-Newtonian fluid mechanics that remain underexplored or inadequately investigated. It highlights on research domains that have not received sufficient attention or detailed study, while also considering the emergence of new areas unexplored by recent scientific and technological advancements. For example explores innovative modeling strategies for understanding fluid dynamics in complex, deformable, and branched flow systems across multiple scales. The elastoviscoplastic (EVP) behavior of fluids under external forcing to model droplet spreading, coalescence, and filtering over porous and soft substrates. Wall slip and junction resistance effects of the flow in tree-like structure. The objective of this paper is to raise awareness about these relatively neglected or unexplored areas of research, encouraging researchers to put efforts towards these promising domains. By doing so, they can contribute to advancing the field in ways that diverge from which have already been sufficiently explored and may lead to breakthroughs and novel discoveries. Moreover, addressing these under-explored areas could have far-reaching implications for both theoretical and practical applications in non-Newtonian fluid mechanics. Investigating these areas more deeply could uncover new insights, enhance existing models, and drive forward technological advancements that were previously overlooked. In addition, this paper will briefly discuss the potential introduction of novel tools, techniques, and methodologies that could be applied to these research areas, as well as to the broader field of non-Newtonian fluid mechanics. These innovations could open up new avenues of exploration and help overcome some of the existing limitations in past and current research.

Spinodal dewetting is the spontaneous rupture and dewetting of thin liquid film (thickness less than 100 nm) on a solid substrate due to the attractive intermolecular forces between the interfaces of the liquid-bounding fluid and the liquid bounded solid substrate. Most of the reported numerical studies are performed by simplification of the Navier–Stokes (NS) equations using lubrication approximation. The lubrication approximation, however, is not valid for all the types of liquid thin films. For example, in metallic films, contact angles are greater than 30o, and inertial forces are also significant. So, to understand thin film dewetting dynamics, there is a need to solve the NS equation without simplification. The present numerical study investigates the spinodal dewetting of thin liquid films under van der Waals force by indirectly solving NS equations using one of the mesoscopic approaches, the lattice Boltzmann method (LBM). The stability analysis is carried out using a single-component multiphase pseudopotential LBM with a multiple relaxation time collision operator at the density ratio of 98.48, in both 2D (two-dimension) and 3D (three-dimension). D2Q9 (D2 represents two-dimension and Q9 represents nine possible microscopic velocities in which a particle can move) and D3Q15 (D3 represents three-dimension and Q15 represents 15 possible microscopic velocities in which a particle can move) lattice models are used in 2D and 3D, respectively. In-house codes are developed using C language, and the 3D LBM codes have been parallelized using a message-passing interface. The reported dewetting stages, namely, the arrangement of fluctuations on a dominant wavelength, hole formation, and expansion, are successfully observed with the present numerical method in both the dimensions. The breakup of liquid threads between the holes into droplets due to Rayleigh instability has also been captured in 3D. In 2D, at the time of initial rupture of the film, the average dominant wavelength [λdom,rupavg] is calculated by DFT (discrete Fourier transform), and it was observed that λdom,rupavg was much greater than that predicted by linear stability analysis λdom,LSA, using lubrication approximation. This study reveals that this deviation can be contributed to the shear stresses present at the interface, high contact angles, and diffused interface.

Hybrid nanocomposites integrating nanostructured zinc oxide (ZnO) and carbon quantum dots (CQDs) with designed heterostructures possess exceptional optical and electronic properties. These properties hold immense potential for advancements across diverse scientific and technological fields. This review article investigates the synthesis, properties, and applications of ZnO‐CQD heterostructure nanocomposites. Recent breakthroughs in fabrication methods are examined, including hydrothermal, microwave‐assisted, and eco‐friendly techniques. Key preparation methods such as sol‐gel, co‐precipitation, and electrochemical deposition are discussed, emphasizing their role in controlling heterostructure formation. This review analyses the impact of heterostructures on optical and electronic properties, such as fluorescence, photoluminescence, and photocatalytic activity. Synergistic interactions between ZnO and CQDs within heterostructures are highlighted, demonstrating how they lead to substantial performance improvements. Applications of ZnO‐CQD heterostructures span solar cells, LEDs, photodetectors, water purification, antimicrobial treatments, gas sensing, catalysis, biomedical imaging, drug delivery, environmental sensing, and energy storage. Insights are provided into refining synthesis methods, enhancing characterisation techniques, and broadening the application landscape. Challenges like stability are addressed, along with strategies for optimised performance and practical implementation. This comprehensive review offers a thorough understanding of ZnO‐CQD heterostructure nanocomposites, emphasising their significance within materials science and engineering. By addressing core concepts and future directions, it lays a foundation for continued innovation in this dynamic field.