It is this strong pH-dependence that selleck inhibitor makes PANI one of the most suitable such information materials to act as a pH-sensitive layer in any pH sensor.One of the main Inhibitors,Modulators,Libraries contributors to research involving PANI in this capacity is Lindfors et al. [25, 32-35]. In their work, the researchers report on using PANI in three different pH-measurement Inhibitors,Modulators,Libraries modes: potentiometric [32], optical [33] and Raman [34, 35]. The results obtained from the research are extremely positive in terms of the applicability of PANI in such applications, with each approach producing an excellent response to pH. An important finding from this research is the solution to the problem of hysteresis (memory effect) that can become a problem when investigating PANI in such an application.
The main advantage of the approach detailed in this paper is that the entire measurement can be miniaturized Inhibitors,Modulators,Libraries for portable applications, unlike many of the Inhibitors,Modulators,Libraries optical techniques that require bulky equipment and are therefore not portable.2.?Experimental SectionIn this work, both thick film and a drop coating approach Inhibitors,Modulators,Libraries were utilized. The thick film screen-printing technique was chosen, as it is cost effective, with the added advantages of repeatability and robustness. Drop coating was investigated, as the PANI material can be quite difficult to screen print due to the agglomeration of polymer particles causing the screen to clog. Drop coating solves this problem by eliminating the mask entirely.
Gold thick film conductor pastes (Hereaus Materials) were first screen-printed onto pre-cleaned alumina substrates (CeramTec UK Ltd.
) Inhibitors,Modulators,Libraries to form an interdigitated electrode (IDE) structure. Gold was chosen as it is an inert material Inhibitors,Modulators,Libraries and is commonly used Cilengitide in chemical sensing devices. The deposition of the conductor paste was achieved using a DEK 1202 automatic screen printer. The resulting IDE structures were placed into an oven Inhibitors,Modulators,Libraries at 80��C for 2 hours to facilitate the initial drying of the pastes. In this oven the remaining solvent in the paste evaporates, leaving the dried pattern on the substrate. The devices are next placed into a furnace for a much higher temperature (850��C) cycle. In this step, any remaining organic binder is removed and the metal frit in the paste is sintered into one solid structure.
This temperature Brefeldin_A cycle also allows the electrode pattern to settle to its final thickness and resistivity values.
The thick film paste required for deposition is obtained by mixing the required mass of PANI powder (Sigma Aldrich) with 10 wt.% polyvinyl butyral (PVB) (acts as a find more info binder), 10 wt.% surfactant (PS3) (stops the agglomeration of polymer particles) and a suitable amount of ethyleneglycolmonobutylether selleck catalog (solvent). This paste is then screen-printed onto the electrodes. The device is placed into an oven at 80��C for 1.5 hours to facilitate solvent evaporation.