Highly Sensitive Optical Sensors Using Electrospun Polymeric Nanofibrous Membranes

2001 ◽  
Vol 708 ◽  
Author(s):  
Xianyan Wang ◽  
Soo-Hyoung. Lee ◽  
Christopher Drew ◽  
Kris J. Senecal ◽  
Jayant Kumar ◽  
...  
Keyword(s):  
Thin Films ◽  
Optical Sensors ◽  
Polyacrylic Acid ◽  
Covalent Attachment ◽  
Layer By Layer ◽  
Electrospun Membrane ◽  
Surface Areas ◽  
Highly Sensitive ◽  
Electrospun Membranes ◽  
Nanofibrous Membranes

ABSTRACTIn recent years, polymer films have found an increasing role in sensors due to their unique characteristics. It is widely accepted that the sensitivity of a film is proportional to the surface area per unit mass. Thin films with very large surface areas can be easily fabricated by electrospinning, wherein a polymer solution is exposed to a high static voltage, creating sub-micron or nanometer scale fibers collected as a non-woven membrane. Electrospun nanofibrous membranes have surface areas approximately one to two orders of the magnitude higher than those found in continuous thin films. It is expected that their sensitivities are potentially as large. In this paper, the first use of an electrospun membrane as a highly responsive fluorescence quenching-based optical sensor is reported. A new fluorescent polymer, polyacrylic acid - poly (pyrene methanol) (PAA-PM), was synthesized via covalent attachment of the fluorescent indicator, pyrene methanol (PM), onto polyacrylic acid (PAA). Optical chemical sensors were then fabricated by electrospinning PAA-PM and thermal crosslinkable polyurethane latex mixture solutions. The synthesis, characterization, electrospinning fabrication, and comparison of the sensitivities to analytes such as ferric ions, mercury, and 2,4-dinitrotoluene between the electrospun membranes and electrostatically layer-by-layer (ELBL) assembled films are presented.

scholarly journals Fabrication of Electrospun Membranes based on Poly(caprolactone) (PCL) and PCL/Chitosan Layer by Layer for Tissue Engineering

2017 ◽  
Vol 17 (1) ◽  
Author(s):  
Choi Yee Foong ◽  
Naznin Sultana
Keyword(s):  
Tissue Engineering ◽  
Contact Angle ◽  
Water Contact Angle ◽  
Water Uptake ◽  
Solution Concentration ◽  
Layered Composite ◽  
Layer By Layer ◽  
Electrospun Membrane ◽  
Water Contact ◽  
Electrospun Membranes

Recently, in the field of tissue engineering, fabrication of three-dimensional (3D) electrospun scaffold or membrane is much emphasized. In this study, layered composite scaffolds or membranes were fabricated using two biodegradable polymers, polycaprolactone (PCL) and Chitosan layer-by-layer with multilayer electrospinning method. Characterizations of membranes were done using several techniques. Electrospun composite membrane’s surface morphology was examined using a Scanning Electron Microscopy (SEM) and the wettability of the material’s surface was determined using water contact angle measuring measurement (WCA). Water uptake properties of electrospun membrane were also determined. Using optimized solution concentration and electrospinning processing parameters, the composite PCL/Chitosan and PCL layer-by-layer were successfully fabricated. It was observed from SEM that the composite electrospun membranes produced consisted microfibers and nanofibers within single scaffold. The water contact angle for the double-layered composite electrospun membranes was lower than the pure PCL. The double-layered composite membrane also had higher water uptake properties compared to pure PCL scaffold.

Electrospun Nanofibrous Membranes for Highly Sensitive Optical Sensors

Nano Letters ◽  
2002 ◽  
Vol 2 (11) ◽  
pp. 1273-1275 ◽  
Author(s):  
Xianyan Wang ◽  
Christopher Drew ◽  
Soo-Hyoung Lee ◽  
Kris J. Senecal ◽  
Jayant Kumar ◽  
...  
Keyword(s):  
Optical Sensors ◽  
Highly Sensitive ◽  
Nanofibrous Membranes

Photoelectric Response from Nanofibous Membranes

2001 ◽  
Vol 708 ◽  
Author(s):  
Kris J. Senecal ◽  
David P. Ziegler ◽  
Jinan He ◽  
Ravi Mosurkal ◽  
Heidi Schreuder-Gibson ◽  
...  
Keyword(s):  
Composite Membranes ◽  
Photovoltaic Devices ◽  
Dye Sensitized ◽  
Photoelectric Response ◽  
Surface Areas ◽  
Phthalocyanine Dyes ◽  
Electrospun Membranes ◽  
Nanofibrous Membranes ◽  
Polymeric Solutions ◽  
Nanoscale Fibers

ABSTRACTElectrospinning has been used to prepare nanofibrous composite membranes of semi-conducting particles (TiO2) and photovoltaic dyes. Electrospinning is a relatively simple technique where electrical forces are used on polymeric solutions to produce nanoscale fibers. The resulting nanofibrous membranes have surface areas that are roughly one to two orders of magnitude higher than conventional thin films. It is believed that this higher surface will allow for more efficient light harvesting in photovoltaic devices. Our research has focused on the fabrication of organic/inorganic hybrid solar cells featuring dye sensitized nanocrystalline semiconductor particles using electrospinning. Phthalocyanine and N3 (cisdi(thiocyanato)bis(2,2'-bipyridyl-4,4'-dicarboxylate) ruthenium(II)) photoactive dyes were electrospun with semi-conductive TiO2 nanoparticles into a matrix polymer, polyacrylonitrile (PAN). Electron microscopy and elemental analysis of the electrospun membranes shows that each component is present and uniformly dispersed in the nanofibrous membranes. In general, the dye membranes electrospun with the TiO2 nanoparticles exhibited a greater photoelectric response than the membranes with dye only. The N3 dye membranes however showed the greatest photoresponse in comparison to the phthalocyanine dyes, with or without the TiO2 nanoparticles. Photoelectric responses on the order of 30 μA and 280 mV were achieved with dye-sensitized membranes and are believed to be the first demonstration of a photoelectric response from an electrospun nanofibrous membrane.

scholarly journals Modeling the Layer-by-Layer Growth of HKUST-1 Metal-Organic Framework Thin Films

Nanomaterials ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1631
Author(s):  
Qiang Zhang ◽  
Yohanes Pramudya ◽  
Wolfgang Wenzel ◽  
Christof Wöll
Keyword(s):  
Thin Films ◽  
Surface Roughness ◽  
Deposition Rate ◽  
Layer Growth ◽  
Coarse Grained ◽  
Structural Defects ◽  
Effect Of Temperature ◽  
Layer By Layer ◽  
Reactant Concentration ◽  
Metal Organic

Metal organic frameworks have emerged as an important new class of materials with many applications, such as sensing, gas separation, drug delivery. In many cases, their performance is limited by structural defects, including vacancies and domain boundaries. In the case of MOF thin films, surface roughness can also have a pronounced influence on MOF-based device properties. Presently, there is little systematic knowledge about optimal growth conditions with regard to optimal morphologies for specific applications. In this work, we simulate the layer-by-layer (LbL) growth of the HKUST-1 MOF as a function of temperature and reactant concentration using a coarse-grained model that permits detailed insights into the growth mechanism. This model helps to understand the morphological features of HKUST-1 grown under different conditions and can be used to predict and optimize the temperature for the purpose of controlling the crystal quality and yield. It was found that reactant concentration affects the mass deposition rate, while its effect on the crystallinity of the generated HKUST-1 film is less pronounced. In addition, the effect of temperature on the surface roughness of the film can be divided into three regimes. Temperatures in the range from 10 to 129 °C allow better control of surface roughness and film thickness, while film growth in the range of 129 to 182 °C is characterized by a lower mass deposition rate per cycle and rougher surfaces. Finally, for T larger than 182 °C, the film grows slower, but in a smooth fashion. Furthermore, the potential effect of temperature on the crystallinity of LbL-grown HKUST-1 was quantified. To obtain high crystallinity, the operating temperature should preferably not exceed 57 °C, with an optimum around 28 °C, which agrees with experimental observations.

Direct Layer-by-Layer Growth of Crystalline Ag-TCNQ Thin Films on Functionalized Au Substrate: How Critical Is the pH of Ag(I) Solution?

2020 ◽  
Vol 11 (24) ◽  
pp. 10548-10551
Author(s):  
Aswani Sathish Lathika ◽  
Shammi Rana ◽  
Anupam Prasoon ◽  
Pooja Sindhu ◽  
Debashree Roy ◽  
...  
Keyword(s):  
Thin Films ◽  
Layer Growth ◽  
Layer By Layer

scholarly journals Layer-by-layer Thin Films and Microcapsules for Biosensors and Controlled Release

2012 ◽  
Vol 28 (10) ◽  
pp. 929-938 ◽  
Author(s):  
Katsuhiko SATO ◽  
Shigehiro TAKAHASHI ◽  
Jun-ichi ANZAI
Keyword(s):  
Thin Films ◽  
Controlled Release ◽  
Layer By Layer

scholarly journals Capacitive Field-effect (bio-)chemical Sensors Based on Nanocrystalline Diamond Films

2009 ◽  
Vol 1203 ◽  
Author(s):  
Matthias Bäcker ◽  
Arshak Poghossian ◽  
Maryam H. Abouzar ◽  
Sylvia Wenmackers ◽  
Stoffel D. Janssens ◽  
...  
Keyword(s):  
Thin Films ◽  
Field Effect ◽  
High Sensitivity ◽  
Ph Sensitive ◽  
Nanocrystalline Diamond ◽  
Penicillin G ◽  
Layer By Layer ◽  
Label Free ◽  
High Coverage ◽  
Layer Adsorption

AbstractCapacitive field-effect electrolyte-diamond-insulator-semiconductor (EDIS) structures with O-terminated nanocrystalline diamond (NCD) as sensitive gate material have been realized and investigated for the detection of pH, penicillin concentration, and layer-by-layer adsorption of polyelectrolytes. The surface oxidizing procedure of NCD thin films as well as the seeding and NCD growth process on a Si-SiO2 substrate have been improved to provide high pH-sensitive, non-porous thin films without damage of the underlying SiO2 layer and with a high coverage of O-terminated sites. The NCD surface topography, roughness, and coverage of the surface groups have been characterized by SEM, AFM and XPS methods. The EDIS sensors with O-terminated NCD film treated in oxidizing boiling mixture for 45 min show a pH sensitivity of about 50 mV/pH. The pH-sensitive properties of the NCD have been used to develop an EDIS-based penicillin biosensor with high sensitivity (65-70 mV/decade in the concentration range of 0.25-2.5 mM penicillin G) and low detection limit (5 μM). The results of label-free electrical detection of layer-by-layer adsorption of charged polyelectrolytes are presented, too.

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