LB Deposition of a Stearic Acid Multilayer without Heavy Metals

Abstract

LB films consisting of stearic acid (SA) multilayers and silicon substrates without heavy metal were prepared using a computer-controlled LB film deposition apparatus. Using dimethyldioctadecylammonium bromide as the first (or first and second) monolayer(s), up to 70 layers were deposited, and the interference color was expressed. This indicated that the surface charge of the substrate needed to be canceled in order to successfully deposit a multilayer. Moreover, it was demonstrated that LB multilayers of fatty acid could be prepared using a computer-controlled apparatus even without using a heavy metal salt.

Design and Fabrication of Biosensor for a Specific Microbe by Silicon-Based Interference Color System

“…Nevertheless, the thickness increased enormously due to the aggregation of more specific microbes (numerous folds) ( Figure 4 B), and the average total thickness calculated for all layers was approximately 420 nm including the oxide layer. This will create a color change, which is attributed to the presence of a surface consisting of a multilayer nanostructure [ 5 ]. The oxide layer also plays a prominent role in the light interference that leads to a color response.…”

“…However, colorimetric detection systems have a fundamental problem detecting specific molecular interactions, such as antibodies or nucleic acids. At the same time, the advantage of the optical platform is that the unaided eye can detect changes in the iridescent color due to several factors such as the nano-ordered film thickness, the number of layers, and the angle of the incident light [ 3 , 4 , 5 , 6 , 7 ]. The chip presented herein is developed especially for the detection of a specific pathogen, Sphingobium yanoikuyae [ 8 , 9 ], which alters the taste of non-beverage alcohols.…”

“…Since those sensors have limited diagnostic ability, they require instrumentation for signal detection [ 18 ]. We have worked for several years on silicon-based iridescent color chips through the coating of various numbers of peptide layers [ 3 , 5 , 6 ]. In this study, we have investigated the application of different numbers of nano-ordered layers of different biomaterials through a step-by-step surface-modification strategy, which provides considerable flexibility in the formation of an iridescent color response for visual sensor applications.…”