Surface modification

About: Surface modification is a research topic. Over the lifetime, 35544 publications have been published within this topic receiving 859567 citations.

Covalently Modified Silicon and Diamond Surfaces: Resistance to Nonspecific Protein Adsorption and Optimization for Biosensing

Abstract: We report the direct covalent functionalization of silicon and diamond surfaces with short ethylene glycol (EG) oligomers via photochemical reaction of the hydrogen-terminated surfaces with terminal vinyl groups of the oligomers, and the use of these monolayers to control protein binding at surfaces. Photochemical modification of Si(111) and polycrystalline diamond surfaces produces EG monolayers linked via Si−C bond formation (silicon) or C−C bond formation (diamond). X-ray photoelectron spectroscopy was used to characterize the monolayer composition. Measurements using fluorescently labeled proteins show that the EG-functionalized surfaces effectively resist nonspecific adsorption of proteins. Additionally, we demonstrate the use of mixed monolayers on silicon and diamond and apply these surfaces to control specific versus nonspecific binding to optimize a model protein sensing assay.

Surface Functionalization of Ti3C2Tx MXene with Highly Reliable Superhydrophobic Protection for Volatile Organic Compounds Sensing

Abstract: Two-dimensional (2D) transition-metal carbides (Ti3C2Tx MXene) have received a great deal of attention for potential use in gas sensing showing the highest sensitivity among 2D materials and good gas selectivity. However, one of the long-standing challenges of the MXenes is their poor stability against hydration and oxidation in a humid environment, limiting their long-term storage and applications. Integration of an effective protection layer with MXenes shows promise for overcoming this major drawback. Herein, we demonstrate a surface functionalization strategy for Ti3C2Tx with fluoroalkylsilane (FOTS) molecules through surface treatment, providing not only a superhydrophobic surface, mechanical/environmental stability but also enhanced sensing performance. The experimental results show that high sensitivity, good repeatability, long-term stability, and selectivity and faster response/recovery property were achieved by the FOTS-functionalized when Ti3C2Tx was integrated into chemoresistive sensors sensitive to oxygen-containing volatile organic compounds (ethanol, acetone). FOTS functionalization provided protection to sensing response when the dynamic response of the Ti3C2Tx-F sensor to 30 ppm of ethanol was measured over in the 5 to 80% relative humidity range. Density functional theory simulations suggested that the strong adsorption energy of ethanol on Ti3C2Tx-F and the local structure deformation induced by ethanol adsorption, contributing to the gas-sensing enhancement. This study offers a facile and practical solution for developing highly reliable MXene based gas-sensing devices with response that is stable in air and in the presence of water.

Simultaneous reduction, functionalization and stitching of graphene oxide with ethylenediamine for composites application

Abstract: A simple, efficient and cost-effective approach for the simultaneous reduction, surface modification and stitching of graphene oxide (GO) using ethylenediamine is described. The effect of stitched graphene on the mechanical properties of linear low density polyethylene (LLDPE)-based composites was also investigated. Ethylamine was used to produce unstitched graphene, of which structures and properties were compared to those of stitched graphene. The surface modification of GO with ethylamine or ethylenediamine can easily take place under mild conditions. The reduced GO (rGO) shows good crystalline behavior and high electrical conductivity (∼1075 S m−1). The removal of epoxide, carboxyl and hydroxyl groups from GO by ethylamine or ethylenediamine was confirmed by Fourier transform infrared, Raman and photoelectron spectroscopy. The microstructures were analyzed by atomic force microscopy and transmission electron microscopy revealing stitching and crystalline behavior of the rGO. Compared to other reported methods, the reduction of GO with ethylamine and ethylenediamine is a preferable route for large-scale production of functionalized graphene. It was found that the storage modulus of the ethylenediamine functionalized GO (3 wt%)–LLDPE composites is significantly higher than that of pure LLDPE or ethylamine functionalized GO reinforced composites in the studied temperature range (−70 to 90 °C).

Non-thermal atmospheric pressure discharges for surface modification

Abstract: A series of different discharge configurations suitable for surface treatment at atmospheric pressure is discussed, including a non-thermal modular radio frequency (13.56, 27.12 or 40.78 MHz) jet plasma.The capacitively coupled configuration allows the operation with both rare gases (e.g. Ar) and reactive gases (N2, air, reactive admixtures of silicon-containing compounds). Several capillaries are arranged in an array to allow plasma assisted treatment of surfaces including non-flat geometries. Optical emission spectroscopy, mass spectrometry and measurements of the axial and radial temperature profiles are used to characterize the discharge.The surface energy of different polymer materials is significantly enhanced after plasma treatment. Many applications are possible, such as plasma activation of surfaces for adhesion control, surface cleaning, plasma enhanced CVD, plasma cleaning, plasma activation and biomedical applications.