Biomimetic Jagged Micropatterns Templated from Photoswitchable Liquid Crystal Topography for Energy Harvesting and Sensing Applications

In this study, an ingenious approach is developed using a fluorocarbon polymer tribosurface with jagged relief patterns, templated from the surface topographic microstructure of a photoresponsive liquid crystal polymer network...

Local Inflammatory Response after Intramuscularly Implantation of Anti-Adhesive Plasma-Fluorocarbon-Polymer Coated Ti6AI4V Discs in Rats

Orthopaedic implants and temporary osteosynthesis devices are commonly based on Titanium (Ti). For short-term devices, cell-material contact should be restricted for easy removal after bone healing. This could be achieved with anti-adhesive plasma-fluorocarbon-polymer (PFP) films created by low-temperature plasma processes. Two different PFP thin film deposition techniques, microwave (MW) and radiofrequency (RF) discharge plasma, were applied to receive smooth, hydrophobic surfaces with octafluoropropane (C3F8) or hexafluorohexane (C6F6) as precursors. This study aimed at examining the immunological local tissue reactions after simultaneous intramuscular implantation of four different Ti samples, designated as MW-C3F8, MW-C6F6, RF-C3F8 and Ti-controls, in rats. A differentiated morphometric evaluation of the inflammatory reaction was conducted by immunohistochemical staining of CD68+ macrophages, CD163+ macrophages, MHC class II-positive cells, T lymphocytes, CD25+ regulatory T lymphocytes, NK cells and nestin-positive cells in cryosections of surrounding peri-implant tissue. Tissue samples were obtained on days 7, 14 and 56 for investigating the acute and chronical inflammation (n = 8 rats/group). Implants with a radiofrequency discharge plasma (RF-C3F8) coating exhibited a favorable short- and long-term immune/inflammatory response comparable to Ti-controls. This was also demonstrated by the significant decrease in pro-inflammatory CD68+ macrophages, possibly downregulated by significantly increasing regulatory T lymphocytes.

Field Trial Comparing Two Materials for Marine Oil Sheen Sampling

The California Department of Fish and Wildlife (CDFW) uses fiberglass material for forensic analysis of oil sheens, while the United States Coast Guard (USCG) method uses a tetrafluoroetheylene-fluorocarbon (TFE-fluorocarbon) polymer net. We performed a field trial of these two materials by sampling natural oil seeps, two in Santa Monica Bay, and three sheen areas in the Santa Barbara Channel. Though the fiberglass material did collect less mass on some trials, the forensic chemistry results demonstrated that both materials were satisfactory for purposes of chemical forensic analysis as each pair of the sampling materials yielded results that were consistent with a common oil seep source.

Characterization of fabrics coated with doped TiO 2 -graphene

This study presents the results of laboratory experiments to prepare cotton woven fabrics with photoactive properties. The fabric was treated with TiO 2 – Fe(1%) – N + 2% graphene by exhaustion followed by a fluorocarbon polymer treatment. The fabric was analyzed by Scanning Electron Microscope coupled with Energy Dispersive Spectroscopy (SEM/EDAX), Differential scanning calorimetry (DSC), Contact Angle measurement, physical properties (weight, thickness, breaking strength, elongation, air/water permeability, electrical resistance). The photocatalytic activity was determined initially and after 5 washings by measuring the trichromatic coordinates of the treated fabrics stained with methylene blue and exposed to UV and visible light on a Hunterlab UV-Vis spectrophotometer. The results demonstrate a uniform deposition of doped TiO 2 -graphene particles on material surface. The thermal stability of the coated cotton fabric is practically unmodified in comparison with blank cotton fabric. The decrease of the surface resistivity demonstrates the deposition of graphene layer, known for its good electrical conductivity. The wetting capacity of initial hydrophilic cotton fabric is dramatically modified, the fabric becoming hydrophobic after treatment. The photocatalytic efficiency is higher under visible light than under UV-radiation due to the TiO 2 doping and decoration with graphene, which extend the light absorption from UV to visible range. The good photocatalytic activity under visible light is maintained after 5 washing cycles.

Universally Applicable Fabrication Technique for Biomimetic Nanocone Arrays on Flexible Polymer Substrates for Anti-Reflection Functionality

Inspired by the anti-reflection functionality of cicada wings decorated with nanocone arrays, a facile technique to endow flexible polymer substrates of diverse chemical compositions with the same functionalities has been devised. In this universally applicable two-step technique based on a capacitatively coupled radiofrequency plasma (CCRP), first oxygen-plasma treatment (OPT) is implemented to grow arrays of vertical elongated nanostructures with almost uniform cross-sectional diameter of the polymer substrate, and then fluorocarbon polymer deposition (FPD) is carried out so that the nanostructures evolve into nanocones with small apex angle. The dependence of ion-bombardment-induced sputtering on the local impingement angle of ions taper the vertical nanostructures into the nanocones during the FPD under CCRP. The nanocone arrays exhibit low specular reflectance in a broad wavelength range and a wide incidence angle range that is quite insensitive to the polarization state of the incident light. The effective refractive index gradient of irregularly arranged nanocone arrays is characterized from the refractive index of the fluorocarbon polymer and the volume fraction considering the nanocone probability with the Gaussian distribution. The excellent broadband and omnidirectional anti-reflection properties are in consequence of a graded refractive index.