Materials for Optical Data Storage

Abstract

The outstanding feature of materials research in the eighties has been the convergence of basic research and practical application, leading to ever shorter cycles of innovation. This is especially true of materials which form the basis of key technologies. The mass storage units of the next generations of computers will be based on optical processes having a storage density which exceeds that of all hitherto known storage techniques that are practicable from the technical standpoint. In view of the fact that since 1982 read-only memories in the form of compact discs (CD-ROM) have become very successful in the field of audio electronics, research and development are now concentrated on materials for write-once (WORM) and erasable (EDRAW) storage systems. Suitable materials for optical data storage are substances in which data markings can be recorded and deleted respectively using semiconductor lasers. Materials development is centered on the synthesis of infrared-absorbing dyes for WORM memories and the production of rare earth/transition metal alloys for magneto-optical data recording. An introduction to CD-ROM technology will be followed by an overview of the state of development of the most important storage materials which are currently available commercially, and then the properties of these materials will be discussed with reference to selected examples.

Fabrication of metallic heat exchangers using sacrificial polymer mandrils

“…To demonstrate the process, we fabricated nickel heat exchangers using PMMA mandrils. The PMMA structures were prepared by microembossing: [17] PDMS molds were filled with granular PMMA, heated at 300 C for 2 h to melt the PMMA particles, and cooled to room temperature. We detached the PMMA mandrils manually from the PDMS molds, and used the procedures described for PU (an initial coating of chromium followed by electrodepostion of nickel) to fabricate metallic microstrucres.…”

Microfabrication, Microstructures and Microsystems

“…In particular, they are transparent in the visible and UV regions and so can be easily adapted to optical detection in microanalytical devices. Microstructures of these materials can be replicated readily using lowcost methods such as replica molding and embossing [55][56][57][58][59][60][61].In addition, the surface properties of these substrates (e. g. wetness ability, adhesion, surface adsorption and surface reactivity) can be modified rationally using a variety of surface chemistries. Techniques involving the formation of self-assembled monolayers (SAMs) [62] and the attachment of complex macromolecules [63] (e.g.…”

“…Injection Molding is an alternative technique used for manufacturing CDs [57]. It has been used to generate microstructures with feature sizes of > 0.5 pm.…”

Side chain polysiloxanes with phthalocyanine moieties

“…Due to their 18-p electron macrocyclic aromatic system, closely related to that of the naturally occurring porphyrin ring, and relative facile tailoring of molecular structure by chemical modification, they found numerous commercial applications, among others: photoconductors in xerography [1], optical data storage [2], solar energy conversion [3], electrochromic and electroluminescent displays [4]. One of the most studied area of the application of phthalocyanines are organic thin film transistors (OTFT) as a potential replacement for silicon-based devices [5], as well as new electronic devices based on field transistor technology such as electronic paper [6] and various types of sensors [7].…”