Growth of Closely Packed Layers of Gold Nanoparticles on an Aligned Ammonium Surface

Abstract

gray levels to phase elements, presenting a continuous modulation of the local height. The experiments presented in this article also give some indications as to the 3D resolution obtainable with this method of stereophotolithography: an in-plane resolution of 1 mm was observed, whereas the out-of-plane resolution was no higher than 30 nm. Such a small voxel size, added to the good correlation between the near optical field properties and the polymerized volume, is most promising as far as applications of this photopolymerizable system to near optical field characterization are concerned. ExperimentalThe photopolymerizable system used in this study consisted of three basic components: a sensitizer dye, an amine cosynergist, and a multifunctional acrylate monomer. Pentaerythritol triacrylate (PETIA) used as received from the supplier forms the backbone of the polymer network. The cosynergist was methyldiethanolamine (MDEA), and eosin Y(2¢,4¢,5¢,7¢-tetrabromofluorescein disodium salt) was used as the sensitizer dye. This system was developed because of its high sensitivity in the spectral region between 450 nm and 550 nm (maximum at 530 nm) and in particular because of its sensitivity to the argon laser light (514 nm) [9]. All the results reported in this paper were obtained with the same reference mixture: 2 wt.-% eosin and 8 wt.-% methyldiethanolamine.An argon laser supplied by Spectra Physics (model 2020) emitting at 514 nm was used as the actinic source. The output power varied from 0.1 to 1.2 W.The polymer thickness was measured with a Nikon interference microscope fitted with a Michelson (5´) or a Mireau objective (10´and 20´). 3D pictures of the polymer microparts were obtained with a UBM optical profilometer.

Nanoparticle Arrays on Surfaces for Electronic, Optical, and Sensor Applications

“…Amine-functionalized substrates bind the particles at a slightly higher density than thiol-functionalized substrates. The dynamics of monolayer assembly has been followed directly by quartzcrystal microgravimetry (QCM) [95,96] and spectroscopy [97] and, for the case of citrate-capped gold particles, occurs over a period of a few hours.…”

“…[76,89,95,113,142,201] The high mass of metallic colloidal particles means that their adsorption is followed very easily (the frequency decreases upon colloid assembly can be as much as 10 000 Hz). [96] For example, colloidal gold particles of about 8 nm in diameter were deposited onto a QCM surface and nonane-1,9-dithiol was used as a linker between the gold layers. [95] Figure 13 shows the mass increase on the QCM surface upon deposition of several layers of the gold colloid.…”

Layer‐by‐Layer Assembly Through Weak Interactions and Their Biomedical Applications

“…This method is called layer‐by‐layer (LbL) assembly, and both basic research and applications have been widely developed in the field of polymer science. Since this technique involves the simple immersion of a substrate into an oppositely charged polymer solution, researchers have extended LbL assembly to include the deposition of not only water‐soluble linear charged‐polymers, but also viruses,13 proteins,14–17 silica colloids,18, 19 metal nanoparticles,20–23 dyes,24–26 metal oxides,27–29 amphiphiles,30, 31 clays,32–34 and polystyrene nanospheres 35–37. At the beginning, only electrostatic interactions were utilized for LbL assembly.…”

Nanoparticle Arrays on Surfaces for Electronic, Optical, and Sensor Applications

“…Amine-functionalized substrates bind the particles at a slightly higher density than thiol-functionalized substrates. The dynamics of monolayer assembly has been followed directly by quartzcrystal microgravimetry (QCM) [95,96] and spectroscopy [97] and, for the case of citrate-capped gold particles, occurs over a period of a few hours.…”

“…[76,89,95,113,142,201] The high mass of metallic colloidal particles means that their adsorption is followed very easily (the frequency decreases upon colloid assembly can be as much as 10 000 Hz). [96] For example, colloidal gold particles of about 8 nm in diameter were deposited onto a QCM surface and nonane-1,9-dithiol was used as a linker between the gold layers. [95] Figure 13 shows the mass increase on the QCM surface upon deposition of several layers of the gold colloid.…”