Method for fabricating pixelated, multicolor polarizing films

Abstract

Pixelated, multicolor polarizing filters--of potential use in full-color displays--were produced by what we believe to be a novel method, i.e., masked evaporation of silver and gold onto glass substrates partially covered with separated sub-micrometer-wide strips of oriented poly(tetrafluoroethylene) (PTFE), prepared by friction deposition. The evaporated metal films preferentially nucleated at the glass surface and, consequently, formed parallel arrays in between the PTFE strips. The structures thus produced feature a strong angle-dependent absorption of polarized visible light, allowing for optical switching between red and blue and between green and yellow.

Metal‐Polymer Nanocomposite Synthesis: Novel ex situ and in situ Approaches

“…Because of unique physical characteristics, gold-polymer nanocomposites are potentially useful for a number of advanced functional applications, especially in the optical and photonic fields. In particular, these materials can be used as light-stable color filters [2], polarizers [3,4], ultra-low refractive index materials [5], nonlinear optical devices [6], optical sensors [7], and so on. However, still limited are the chemical routes that allow us to obtain monodispersed thiolderivatized gold nanoparticles with controlled size to be embedded into poly-meric matrices.…”

“…The analysis of the plasmon peak may give morphological-topological information on the produced cluster system, and in particular the average size of nanoparticles. According to the literature [10], the maximum absorption value, A max , is related to the number of absorption centers, N, and to the average particle radius, R, by the following semiempirical expression: (2) where k is a proportionality constant and 2.8 is a semiempirical factor (the theoretical value is 3). Therefore, if the number of gold particles, N, is a constant during the metal phase-separation process, the cubic root of the maximum absorption value is proportional to cluster radius and such information can be used to study the mechanism of cluster growth.…”

“…At temperatures higher than 70°C for a PVP/HAuCl 4 weight ratio of 400, the nucleation of gold is fast enough; consequently, nucleation and growth are separated stages of cluster formation, and the number of particles is practically a constant during the radial development of clusters. In this case, a correct evaluation of cluster size can be obtained by using equation (2). However, since the proportionality constant, k, is unknown, TEM calibration, measurements should be used.…”

“…Without calibration, only the profile of the temporal evolution of cluster radius can be obtained. The results of the analysis of spectral data obtained above 70°C by using equation (2) are shown in Figure 5.6a. As visible above 70°C, the cluster radius increased according to a linear function of time.…”

Structural analysis and shape-dependent catalytic activity of Au, Pt and Au/Pt nanoparticles

“…Because of unique physical characteristics, metal-polymer nanocomposites are potentially useful for a number of advanced functional applications, especially in the optical, catalysis and photonic fields. In particular, these materials can be used as light-stable color filters [7], polarizers [8,9], ultra-low refractive index materials [10], nonlinear optical devices [11], optical sensors [12], and so on. However, the chemical routes that allow us to obtain monodispersed metallic nanoparticles with controlled size are still limited.…”