We present scanning force microscope images of craterlike defects induced by individual 78.2-MeV ${}_{}{}^{127}{}_{}{}^{}\mathrm{I}$ ions incident on organic single-crystal L-valine surfaces. For grazing incidence ions, the craters are elongated along the ion azimuth of incidence and display a raised tail in the surface above the ion track. This permanent plastic deformation of the surface indicates that a hydrodynamic pressure-pulse phenomenon occurs in response to the electronically deposited energy.

Anomalies in atomic force microscopy (AFM) based size determination of nanoparticles were studied via comparative analysis of experiments and numerical calculations. Single tungsten oxide nanoparticles with a mean diameter of $3\mathrm{nm}$ were deposited on mica and graphite substrates and were characterised by AFM. The size (height) of the nanoparticles, measured by tapping mode AFM, was found to be sensitive to the free amplitude of the oscillating tip, thus indicating that the images were not purely topographical. By comparing the experimental results to model calculations, we demonstrate that the dependence of the nanoparticle size on the oscillation amplitude of the tip is an inherent characteristic of the tapping mode AFM; it is also a function of physical properties such as elasticity and surface energy of the nanoparticle and the sample surface, and it depends on the radius of curvature of the tip. We show that good approximation of the real size can easily be obtained from plots of particle height vs free amplitude of the oscillating tip, although errors might persist for individual experiments. The results are valid for size (height) determination of any nanometer-sized objects imaged by tapping mode AFM.

Even-numbered positive-ion carbon clusters (${\mathrm{C}}_{2\mathit{n}}$, n=20,21,...) are ejected from a solid film of organic polymer—poly(vinylidene difluoride) (PVDF)—when bombarded by MeV atomic ions. Carbon-cluster ions are formed as a result of a single primary-ion impact. The distribution of cluster sizes suggests that the clusters have closed carbon-cage (fullerene) structure. Measurements of the yield and initial-velocity distributions of the ejected cluster ions are performed in a time-of-flight mass spectrometer equipped with an electrostatic ion mirror. The results are compared to data for ions ejected by MeV projectiles from films of synthetic fullerene (${\mathrm{C}}_{60}$ and ${\mathrm{C}}_{70}$) targets. The initial-radial-velocity distribution for cluster ions ejected from the polymer differ markedly from those of synthetic fullerene targets. While ${\mathrm{C}}_{60}$ and ${\mathrm{C}}_{70}$ ions from synthetic fullerene targets have ejection-angle distributions symmetric with respect to the target-surface normal, the mean takeoff angle of carbon-cluster ions ejected from PVDF is off-normal and towards the direction of the incoming primary ion. It is also a clear indication that carbon-cluster ions ejected from PVDF originate in the high-energy-density region created by the fast primary ion. Experiments for establishing the dependence of the carbon-cluster yield Y on the energy loss of the primary ion have been performed. A stronger dependence of the yield for the ${\mathrm{C}}_{60}$ ions desorbed from PVDF targets [Y∝(dE/dx${)}^{3.4}$] than for ions from targets with synthetic ${\mathrm{C}}_{60}$ [Y∝(dE/dx${)}^{2.0}$] has been observed. This supports the conclusion that carbon-cluster ions from PVDF are formed in the axially expanding high-energy-density plasma region.

Enhancing the performance of polymeric membranes by nanomaterials has become of great interest in the field of membrane technology. The present work aimed to fabricate polyvinylidene fluoride (PVDF)-hybrid nanocomposite membranes and modify them with TiO₂ and/or BiVO₄ nanoparticles and/or carbon nanotubes (CNTs) in various ratios. Their photocatalytic performance under visible light was also investigated. All modified PVDF membranes exhibited higher hydrophilicity (lower contact angle of water droplets) than that of the neat membrane used as a reference. The membranes were characterized by using bovine serum albumin (BSA) as model dairy wastewater. The hybrid membranes had better antifouling properties as they had lower irreversible filtration resistance than that of the neat membrane. Hybrid PVDF membranes containing TiO₂/CNT/BiVO₄ showed the highest flux and lowest irreversible resistance during the filtration of the BSA solution. PVDF-TiO₂/BiVO₄ had the highest flux recovery ratio under visible light (70% for the PVDF mixed with 0.5% TiO₂ and 0.5% BiVO₄). The hydrophilicity of membrane surfaces increased with the incorporation of nanoparticles, preventing BSA to bind to the surface. This resulted in a slight decrease in BSA and chemical oxygen demand rejections, which were still above 97% in all cases.