Morphological and Semi-empirical Study of the Pluronic F68/Imogolite/Sudan III Intersurfaces Composite for the Controlled Temperature Release of Hydrophobic Drugs

Some PluronicF68 (F68) triblock copolymer properties demonstrate surprising applications in selective drug administration, such as the transportation of hydrophobic anti-inflammatories through epithelial barriers. Nuclear magnetic resonance (¹H-NMR) spectroscopy was carried out for micelle precursor dispersions and F68 films modified with a synthetic imogolite (IMO) biocompatible hydrogel. Theoretical calculations and morphological assessment for the process of morphogenesis of dendritic crystallization were performed by molecular docking and atomic force microscopy (AFM) of the Sudan III-IMO-F68 composite, which was more hydrophobic than Sudan III-F68 and carried out the prolonged release of the Sudan III "drug" captured by a water-octanol interface determined by standard absorbance. Surface fusions were measured and compared to the unmodified matrix. However, despite the superior properties of the composite, the critical micelle concentration (CMC) was practically unmodified because solitary IMO strands attached to Sudan III formed Sudan III-IMO. These strands unraveled in a stable manner by expanding like a "spiderweb" in hydrophilic interfaces according to NMR analysis of the hydrogen one H₁ polarization of Sudan III and F68 methyl, whose correlation relates hydrophobicity of Sudan III-IMO-F68 with dendrite properties from F68 concentrations. CMC and surface fusions equivalent to F68 surface properties, calculated by differential scanning calorimetry and dynamic Raman spectroscopy, were determined by AFM and high-resolution ellipsometry. Our results show highly specialized pharmacological applications since micelle surfaces expand, triggering maximum deliveries of "Drugs" from its interior to the physiological environment. The implanted sensor prototype determined equilibria reached Sudan III according to temperature (32-50 °C) and time it took to cross the membrane model 1-octanol (48 h). The findings suggest that the targested design of a F68-IMO-"Drug" would function as a microdevice for the prolonged release of hydrophobic drugs. In addition, the said microdevice could regenerate the damaged tissue in the central nervous system or other organs of the body. This is due to the fact that it could perform both tasks simultaneously, given the properties and characteristics acquired by the compatible material depending on the temperature of the physiological environment.

Conductive properties of switchable photoluminescence thermosetting systems based on liquid crystals

Conductive properties of different thermosetting materials modified with nematic 4'-(hexyl)-4-biphenyl-carbonitrile (HBC) liquid crystal and rutile TiO(2) nanoparticles were successfully studied by means of tunneling atomic force miscroscopy (TUNA). Taking into account the liquid crystal state of the HBC at room temperature, depending on both the HBC content and the presence of TiO(2) nanoparticles, designed materials showed different TUNA currents passed through the sample. The addition of TiO(2) nanoparticles into the systems multiply the detected current if compared to the thermosetting systems without TiO(2) nanoparticles and simultaneously stabilized the current passed through the sample, making the process reversible since the absolute current values were almost the same applying both negative and positive voltage. Moreover, thermosetting systems modified with liquid crystals with and without TiO(2) nanoparticles are photoluminescence switchable materials as a function of temperature gradient during repeatable heating/cooling cycle. Conductive properties of switchable photoluminescence thermosetting systems based on liquid crystals can allow them to find potential application in the field of photoresponsive devices, with a high contrast ratio between transparent and opaque states.

Relationships between the morphology and thermoresponsive behavior in micro/nanostructured thermosetting matrixes containing a 4'-(hexyloxy)-4-biphenylcarbonitrile liquid crystal

Meso/nanostructured thermoresponsive thermosetting materials based on an epoxy resin modified with two different molecular weight amphiphilic poly(styrene- block-ethylene oxide) block copolymers (PSEO) and a low molecular weight liquid crystal, 4'-(hexyloxy)-4-biphenylcarbonitrile (HOBC), were investigated. A strong influence of the addition of PSEO on the morphology generated in HOBC--(diglicydyl ether of bisphenol A epoxy resin/ m-xylylenediamine) was detected, especially in the case of the addition of PSEO block copolymers with a higher PEO-block content and a lower molecular weight. The morphologies generated in the ternary systems also influenced the thermoresponsive behavior of the HOBC separated phase provoked by applying an external field, such as a temperature gradient and an electrical field. Thermal analysis of the investigated materials allowed for a better understanding of the relationships between generated morphology/thermo-optical properties/PSEO:HOBC ratio, and HOBC content. Controlling the relationship between the morphology and thermoresponsive behavior in micro/nanostructured thermosetting materials based on a 4'-(hexyloxy)-4-biphenylcarbonitrile liquid crystal allows the development of materials which can find application in thermo- and in some cases electroresponsive devices, with a high contrast ratio between transparent and opaque states.

Liquid crystal alignment in electro-responsive nanostructured thermosetting materials based on block copolymer dispersed liquid crystal

Novel well-defined nanostructured thermosetting systems were prepared by modification of a diglicydylether of bisphenol-A epoxy resin (DGEBA) with 10 or 15 wt% amphiphilic poly(styrene-b-ethylene oxide) block copolymer (PSEO) and 30 or 40 wt% low molecular weight liquid crystal 4'-(hexyl)-4-biphenyl-carbonitrile (HBC) using m-xylylenediamine (MXDA) as a curing agent. The competition between well-defined nanostructured materials and the ability for alignment of the liquid crystal phase in the materials obtained has been studied by atomic and electrostatic force microscopy, AFM and EFM, respectively. Based on our knowledge, this is the first time that addition of an adequate amount (10 wt%) of a block copolymer to 40 wt% HBC-(DGEBA/MXDA) leads to a well-organized nanostructured thermosetting system (between a hexagonal and worm-like ordered structure), which is also electro-responsive with high rate contrast. This behavior was confirmed using electrostatic force microscopy (EFM), by means of the response of the HBC liquid crystal phase to the voltage applied to the EFM tip. In contrast, though materials containing 15 wt% PSEO and 30 wt% HBC also form a well-defined nanostructured thermosetting system, they do not show such a high contrast between the uncharged and charged surface.