Self-Assembled Gold Nanoparticle/Dendrimer Composite Films for Vapor Sensing Applications

Abstract

Vapor-sensitive thin-film resistors comprising gold nanoparticles and different types of organic dendrimers (polyphenylene, poly(propylene imine) and poly(amidoamine)) were prepared via layer-by-layer self-assembly and characterized by UV/vis spectroscopy, atomic force microscopy, and conductivity measurements. While the metal nanoparticles were utilized to provide the film material with electric conductivity, the dendrimers served to cross-link the nanoparticles and to provide sites for the selective sorption of analyte molecules. Dosing the films with vapors of toluene, 1-propanol, and water significantly increased the film resistances. The chemical selectivity of this response was controlled by the solubility properties of the dendrimers.

Self‐Assembly of Nanoparticles on Live Bacterium: An Avenue to Fabricate Electronic Devices

“…Thus, a combination of the exponential dependence on a and that a ≈ 2.3 nm explains the high sensitivity of the system. Furthermore, in contrast to the earlier reports on gold nanoparticle/organic composite thin-film sensors [8][9][10] in which electron transport takes place by thermionic emission or activated tunneling, electron transport in our device takes place through tunneling because the activation energy for tunneling is approximately 1.7 meV (see Figure 6), which is much lower than the thermal energy of a free electron (k T ≈ 25 meV) at room temperature. In summary, we have illustrated an approach to fabricate an active hybrid bioelectronic device using physical nanomaterials and a live microorganism.…”

“…Vapor sensors based on the increase in resistance due to separation of Au nanoparticles have been reported in three-dimensional (3D) clusters of Au nanoparticle/organic composite films. [8][9][10] In the present study, the coupling between the large expansion of an underlying hygroscopic bacterium membrane and the monolayer of Au particles is key to achieving a larger change in current, by an order of magnitude, relative to the above-mentioned 3D nanocomposite devices, for which the change in current results from the swelling of an interparticle organic phase. The method shown herein could be used to pattern various nanoscale inorganic materials, whose optical, electrical, and magnetic properties could be biologically controlled, and thereby lead to an important advance in the present technology.…”

Hairy nanoparticle assemblies as one-component functional polymer nanocomposites: opportunities and challenges

“…[45,131] For example, Krasteva et al [132] have fabricated dendrimer/gold nanoparticle sensors where the dendrimers swell in the presence of solvent vapors, changing the interparticle distances between the gold particles and thus the electrical conductivity of the films. This approach is readily extensible, as the correct choice of corona can allow for the sensing of a wide range of volatile compounds, since, as seen earlier, the various brush conformation models indicate that the size of the corona not only depends on the interaction parameter between the solvent and the corona, but also on the initial HNP design.…”

Nanostructured CaWO4, CaWO4:Eu3+ and CaWO4:Tb3+ Particles: Sonochemical Synthesis and Luminescent Properties

“…23 Metal nanoparticles dispersed in polymeric matrices may result in increased stability, improved processability and enhanced catalytic properties. [24][25][26] Among various conducting polymers, polyaniline (PANI) has been widely investigated due to its unique conduction mechanism and high environmental stability. 27 The composite of AuNPs-PANI exhibits both charge transfer effect and charge transfer induced conductance switching suitable for memory device.…”