Langmuir–Blodgett trough

Since then, LB films (and subsequently the troughs to make them) have been used for a wide variety of scientific experimentation, ranging from 2D crystallization of proteins to Brewster angle microscopy.The monolayer's effect on the surface pressure of the liquid is measured through use of a Wilhelmy plate, electronic wire probes, or other types of detectors.In addition to amphiphilic materials, Langmuir-Blodgett Troughs are commonly used nowadays to create nanoparticle coatings with controlled packing density.In their first experiments, Langmuir and Blodgett used flexible silk threads rubbed with wax to enclose and compress the monolayer film.These barriers are typically made from hydrophilic POM to form a meniscus on them that will aid in keeping the molecules inside even in high packing densities.Additionally, it is important to maintain constant surface pressure during deposition in order to obtain uniform LB films.The surface tension can then be calculated by the following equation: where The weight of the plate can be determined beforehand and set to zero on the electrobalance, while the effect of buoyancy can be removed by extrapolating the force back to the zero depth of immersion.[9] Pockels continued her work and in 1892 published a paper in which she calculated the amount of several materials (mostly household oils) required to form a monolayer.[10] In a later paper Pockels examined the effects of different ratios of hydrophobic to amphiphilic molecules on surface tension and monolayer formation.[3] Neil Kensington Adam summarized and expanded on the work of Langmuir in a series of several papers published in Proceedings of the Royal Society of London from 1921 to 1926.[14] Katherine Blodgett was a student of Irving Langmuir and in 1935 she described the deposition of hundreds of layers of amphiphilic molecules onto a solid substrate in a very ordered fashion.If an aqueous subphase is used, the water must be purified to remove organics and deionized to a resistivity not less than 1.8 GΩ-m. Impurities as small as 1ppm can radically change the behavior of a monolayer.[20] Troughs can be used to make films for the fabrication of nanoscale electronics such as graphene sheets (Li et al., 2008), and LCDs (Russell-Tanner, Takayama, Sugimura, DeSimone & Samulski, 2007).An example of Langmuir–Blodgett troughs' utility in characterizing Langmuir films is the analysis of surface properties of quantum dots at the air-water interface.[22] This feature makes Langmuir troughs a suitable candidate for synthesis and characterization of covalent monolayer sheets and even 2D polymers.