We describe a novel technique for the characterization of the mean pore radius of self-ordered porous anodic alumina membranes. We have studied the flow of liquids through cylindrical membrane pores under conditions of very low Reynolds number (Re ≪ 1). We find that the flow data are well-described by Poiseuille's law. Characterization is achieved through the application of the Hägen-Poiseuille equation on flow measurements conducted in a simple and compact experimental setup. This setup allows for the monitoring of flow as a result of the pressure difference between the two sides of the membrane without the use of sophisticated and costly laboratory equipment. The proposed method has been tested by flow experiments using liquids of various viscosities. Good agreement is found between the results obtained from the flow data and the pore radii measured by scanning electron microscopy. Consistent results for the mean pore radius for the same membrane have been obtained in all cases.

We have investigated the flow of liquids through anodic alumina membranes with cylindrical nanopores bearing asymmetric polystyrene (PS)−polyethylene oxide (PEO) block copolymer brushes, where the short PEO block acts as an anchor on the alumina surface. The flow is well described by Poiseuille's law, which allows determination of the hydrodynamic brush height within the nanopores. The height of the brushes in good solvent is found to vary systematically with the PS molecular weight, M w , consistent with a power law of the form M w 3/5 . Dramatic changes in the flow rate are observed as a function of solvent quality, which is tuned by varying the ratio of good to poor solvent (toluene to cyclohexane, respectively) in the solvent mixture. Flow control is achieved via the regulating effect triggered by the spontaneous and reversible response of the brush height to the quality of the solvent flowing through the membrane nanopores.

Paper-like hybrid films based on carbon nanotubes (CNTs) are considered as favorable materials for electromagnetic interference shielding, energy storage, water treatment, and other contemporary high-performance applications due to their unique combination of excellent physical properties, multifunctional capabilities, and ease of fabrication. The present work reports the development, mechanical, electrical, and thermal characterization of multiwalled CNTs-based paper-like networks supporting a wide variety of two-dimensional graphene related materials (2D GRMs), in the absence of a matrix, for rapid de-icing applications. A multitude of hybrid CNT/GRM papers were produced, using graphene oxide (GO), chemically reduced GO, thermally reduced GO, and graphene nanoplatelets at weight fractions ranging from 0 up to 100 wt %. The mechanical response of the papers under uniaxial tension revealed that their toughness was dependent on both the 2D GRM type and nanotube modification method, while the materials exhibited a favorable combination of multifunctional behavior and mechanical robustness. The latter was evidenced by high values of Young's modulus of up to 13 GPa, an ultimate strength of up to 120 MPa, and a fracture energy of up to 1.84 MJ/m 3 . High values of electrical conductivity of up to ca. 12,500 S/m were coupled with dramatically fast heating responses to temperatures above 300 °C due to the Joule heating effect, which reached unprecedented rates of 355 °C/s and brought forward an impressive potential of the materials for electrothermal applications. In particular, the observed unique combination of low power draw, up to 16 W, high heating power densities of ca. 40,000 W/m 2 , and small mass renders the films ideal candidates for de-icing applications with a negligible weight burden on critical surfaces.

Ultrathin carbon nanomembranes (CNMs) are two−dimensional materials (2DM) of a few nm thickness with sub−nm intrinsic pores that mimic the biofiltration membranes found in nature. They enable highly selective, permeable, and energy−efficient water separation and can be produced at large scales on porous substrates with tuned properties. The present work reports the mechanical performance of such CNMs produced by p−nitrobiphenyl phosphonic acid (NBPS) or polyvinylbiphenyl (PVBP) and their composite membranes of microporous supporting substrates, which constitute indispensable information for ensuring their mechanical stability during operation. Measuring the nanomechanical properties of the ultrathin material was achieved by atomic force microscopy (AFM) on membranes both supported on flat substrates and suspended on patterned substrates (“composite membrane”). The AFM analysis showed that the CNMs presented Young’s modulus in the range of 2.5–8 GPa. The composite membranes’ responses were investigated by tensile testing in a micro−tensile stage as a function of substrate thickness and substrate pore density and diameter, which were found to affect the mechanical properties. Thermogravimetric analysis was used to investigate the thermal stability of composite membranes at high temperatures. The results revealed the structural integrity of CNMs, while critical parameters governing their mechanical response were identified and discussed.