The use of block copolymers as a sacrificial template has been demonstrated to be a powerful method for obtaining porous carbons as electrode materials in energy storage devices. In this work, a block copolymer of polystyrene and polyacrylonitrile (PS--PAN) has been used as a precursor to produce fibers by electrospinning and powdered carbons, showing high carbon yield (~50%) due to a low sacrificial block content ( ≈ 0.16).
View Article and Find Full Text PDFEpoxy resins are thermosets with interesting physicochemical properties for numerous engineering applications, and considerable efforts have been made to improve their performance by adding nanofillers to their formulations. MXenes are one of the most promising functional materials to use as nanofillers. They have attracted great interest due to their high electrical and thermal conductivity, hydrophilicity, high specific surface area and aspect ratio, and chemically active surface, compatible with a wide range of polymers.
View Article and Find Full Text PDFThe functionalization of smart polymers is opening a new perspective in catalysis, drug carriers and biosensors, due to the fact that they can modulate the response regarding conventional devices. This smart response could be affected by the presence of organometallic complexes in terms of interactions which could affect the physical chemical properties. In this sense, the thermoresponsive behavior of copolymers based on -isopropylacrylamide (NIPAM) could be affected due to the presence of hydrophobic groups and concentration effect.
View Article and Find Full Text PDFPolyetheretherketone (PEEK)/polyetherimide (PEI) blends (50/50, ) keeping the crystal phase of PEEK have been manufactured by alternate PEEK/PEI layer stacking. This strategy avoided the complete miscibility of both polymers, keeping layers of PEEK and PEI unmixed along the sample thickness, as well as promoting the formation of a smooth interfacial layer where PEEK and PEI were mixed. The properties of this interface after processing at molten state and different times was studied by DSC, DMA, and X-Ray synchrotron.
View Article and Find Full Text PDFMagneto-mechanically active surfaces (MMAS) represent a new family of nano/micro-structured surfaces in which motion is induced by an external magnetic field. Under the name of "artificial cilia", "biomimetic cilia", "magnetic actuated patterns", "nanopillars", etc., published works in this area continue their quick growth in number.
View Article and Find Full Text PDFMacromol Rapid Commun
February 2013
Photoremovable protecting groups (PRPGs) are applied to organic surfaces, thin polymer films, and hydrogels to achieve light-based remote control of their (bio)chemical and physical properties. These can be localized (i.e.
View Article and Find Full Text PDFInspired by the amino acid 2-chloro-4,5-dihydroxyphenylalanine (Cl-DOPA), present in the composition of the proteinaceous glue of the sandcastle worm Phragmatopoma californica, a simple strategy is presented to confer antifouling properties to polymer surfaces using (but not releasing) a bioinspired biocide. Cl-Dopamine is used to functionalize polymer materials and hydrogel films easily, to prevent biofilm formation on them.
View Article and Find Full Text PDFPhotoreactive surfaces derived from a new photocleavable surface modification agent and with photosensitivity in the Vis and IR region are described. A ruthenium(II) caged aminosilane, [Ru(bpy)(2)(PMe(3))(APTS)](PF(6))(2), was synthesized and attached to silica surfaces. Light irradiation removed the cage and generated surface patterns with reactive amine groups.
View Article and Find Full Text PDFWe report the synthesis and properties of a photoactivatable caged RGD peptide and its application for phototriggering integrin- and cell-binding to surfaces. We analysed in detail 1) the differences in the integrin-binding affinity of the caged and uncaged forms by quartz crystal microbalance (QCM) studies, 2) the efficiency and yield of the photolytic uncaging reaction, 3) the biocompatibility of the photolysis by-products and irradiation conditions, 4) the possibility of site, temporal and density control of integrin-binding and therefore human cell attachment, and 5) the possibility of in situ generation of cell patterns and cell gradients by controlling the UV exposure. These studies provide a clear picture of the potential and limitations of caged RGD for integrin-mediated cell adhesion and demonstrate the application of this approach to the control and study of cell interactions and responses.
View Article and Find Full Text PDFThe possibility of wavelength-selective cleavage of seven photolabile caging groups from different families has been studied. Amine-, thiol-, and carboxylic-terminated organosilanes were caged with o-nitrobenzyl (NVOC, NPPOC), benzoin (BNZ), (coumarin-4-yl)methyl (DEACM), 7-nitroindoline (DNI, BNI), and p-hydroxyphenacyl (pHP) derivatives. Caged surfaces modified with the different chromophores were prepared, and their photosensitivity at selected wavelengths was quantified.
View Article and Find Full Text PDFMultilayers formed by the sodium salt of poly(4-styrenesulfonate), PSS, and triblock copolymers of the form PDMAEMA-PCL-PDMAEMA (PDMAEMA corresponding to poly[2-(N,N-dimethylamino)ethyl methacrylate), and PCL to poly(epsilon-caprolactone) have been built by layer-by-layer self-assembly from the aqueous polyelectrolyte solutions. Two types of block copolymers have been used which differ on the type of the amino groups, either hydrochloride or quaternized. This leads to changes in the charge density of the chains for the same content of amino groups.
View Article and Find Full Text PDFBSA and lysozyme have been transformed into macroinitiators for living radical polymerisation and used to produce well-defined bioconjugates which can be fluorescently labelled providing a versatile strategy for the preparation of bioconjugates which is complementary to traditional PEGylation.
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