QUESTION 7

For the following text, indicate which would be the most appropriate aim for the research. In recent years, the use of organic materials (polymers, monomers, etc.) in electronic device fabrication has shown a rapid increase. In this period there have been substantial advances in materials and devices, such as organic light emitting diodes (Tang & VanSlyke 1987), organic field-effect transistors (Garnier et al. 1994) and solar cells (Yu et al. 1995), with some devices being developed to the point of commercialization. The actors driving this growth can be attributed to the overall low cost of organic devices, material tailoring for specific properties, simple device structures, low-temperature manufacturing processes and compatibility of organic materials with cheap flexible substrates. In the field of organic memory devices, progress can be broadly split into two categories, namely molecular memory devices and polymer memory devices. In the case of molecular memory, a monolayer of molecules is deposited between metal electrodes (Reed et al. 2001). In a polymer memory device, an admixture (a blend) of small organic molecules and/or metal nanoparticles in a polymer matrix is deposited between metal electrodes to form an array of memory elements (Paul et al. 2006). Albeit there have been a number of demonstrations of polymer and nanoparticle blends in emerging electrical memory devices, their working principle is not as yet very clear. In this paper, we attempt to answer some of the questions concerning the memory effect by intentionally incorporating electric dipoles (using ferroelectric nanoparticles) in the polymer matrix. Molecular memories have proved difficult to manufacture, with large variations between device characteristics. However, polymer memory devices, in contrast, are typically fabricated by the spin-coating technique and have shown a great deal of promise as a future memory technology.

A.

The aim of this research is to develop a new technique to fabricate the both polymer and molecular memories.

B.

The aim of this research is to fabricate by spin-coating technique the polymer memory devices

C.

The aim of this research is to investigate the switching mechanism in the molecular memories

D.

The aim of this research is an exploration of memory effect in polymer memories based on ferroelectric nano particles

QUESTION 8

For the following text, indicate which would be the most appropriate aim for the research.

Material extrusion can be used to build a 3D part via extruding a thermoplastic-based filament through a hot printhead and subsequently depositing the melt in layer-by-layer. Nevertheless, the material is subjected to a three-step melt process including 1) mixing of different compounds, 2) extruding filament feedstock and 3) material extrusion. This extended processing results in a long residency time and excessive thermal decomposition of PVOH. To address this issue, a pellet-fed material extrusion system has been developed and used combining Additive manufacturing (AM) with a conventional single-screw extrusion. Pellet materials can be processed directly using this technology. Therefore, the residual time of polymer melt is significantly reduced as pre-processes to compound and extrude filament are not required. It is an ideal technology to process heat-sensitive polymers or materials that are difficult to extrude into filament with a consistent diameter. Additionally, this technology allows co-processing of multiple materials at different and variable rates fed into the extruder to fabricate a compositionally heterogeneous structure. Commercially available pellet-fed material extrusion systems include 3DDiscovery (regenHU, Switzerland) focused on biomaterials, Gigabot X (re:3D Inc., US), ATLAS (Titan Robotics, US) and BAAM (Cincinnati, US). However, these have emerged onto the market within the time-frame of this research. The vast majority of material extrusion system are still using filament feedstock. This study proposes an AM technology that is more appropriate for processing heat-sensitive material, in particular PVOH.

	A.	The aim of this project is to demonstrating 3D printing capability of PVOH structures
	B.	The aim of this research is to build a 3D part via extruding a thermoplastic-based filament via conventional AM
	C.	The aim of this research is to develop pellet-fed material extrusion system