Optically Transparent, Electrically Conductive Composite Medium

Abstract

The development of an optically transparent yet electrically conductive material made with a composite structure having preferentially arranged conductive paths is described. The medium contains many vertically aligned but laterally isolated chains of ferromagnetic spheres dispersed in a sheet of transparent polymer. The sheet material transmits more than 90 percent of the incident light and is highly conductive only in the thickness direction. When suitably modified, the material exhibits on-off electrical switchability at a certain threshold pressure. These characteristics confer potential usefulness for visual communication devices such as write pads or touch-sensitive screens.

Optical properties of composite membranes containing arrays of nanoscopic gold cylinders

“…While bulk metals are optically opaque, effective medium theory (EMT) [41 predicts that collections of small metal particles can be transparent, provided that the wavelength of light employed is much greater than a characteristic dimension of the particle [4]. Hence, EMT can be used as a guide to prepare metal-containing composites that are both electronically conductive and optically transparent [5][6][7][8]. Such composites are inherently interesting from a purely scientific viewpoint and have a variety of possible technological applications [7].…”

Preparation and characterization of multifunctional free-standing Ni/epoxy composite films

“…Because they are in a fluid epoxy medium before curing, the Ni particles will move to minimize the potential energy of the system. The resultant magnetic dipoles in the neighboring columns repel each other, thus positioning the columns towards an equilibrium spacing [14]. The surface tension of the epoxy matrix prevents the undesirable overgrowth of the Ni columns beyond the thickness of the layer.…”

“…Especially, optically transparent, mechanically flexible but electrically conductive and ferromagnetic material films are very useful in practical applications for flexible multifunctional devices in various electronic and electro-optical [5,6], magneto-optical recording [7,8], surface mount [9,10] and new sensor technologies [11,12]. Polymer based composites are nowadays more and more considered as promising candidates for this kind of applications [13][14][15]. Transparent polymers such as poly(vinyl alcohol) (PVA) and epoxy resin, etc.…”

“…Thermosetting polymers have the advantages such as ease of processability and low cost of production, etc. Epoxy resins are a class of extensively used thermosetting polymers and their multifunctional composites have wide applications in surface mount, space and electronic technologies [14,15,21]. Unfortunately, the resultant composites usually become opaque by the introduction of functional particles.…”

Elastomer Application in Microsystem and Microfluidics

“…These materials exhibit Z-direction only electrical conduction, in combination with the compliant nature of the materials, can be exploited advantageously for a variety of electronic applications, including fine-pitch, area-array, circuit interconnects, circuit-testing, heat sink interfacing, and sensor devices 47,48 . The schematic diagram of this design structure is shown in Figure 1.…”