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Polymer Science and Engineering - مطالب ابر materials

Nanostructured and Functionalized Materials & Devices

Materials for biomedical applications

Molecular functionalization techniques are used to tailor substrates for biomedical applications. Examples include microbicidal surfaces which inhibit biofilm formation; high strength bone cements with bactericidal biopolymers or antibiotic-conjugated monomers which achieved higher antibacterial efficacy longer than the present cements; and magnetic nanoparticles for bioimaging and tumor targeting. In a separate development, the adsorption disruption of oriented liquid crystal molecules on a patterned surface was developed into a new label-free optical method for the simultaneous detection of multiple glycine oilgomers using sample size as little as 2 μL.

Materials for energy applications

Research in energy is focused on the design and synthesis of new and alternative materials for energy supply, transformation, storage, delivery and end-use. There are strong coordinated efforts in developing catalysts for fuel production, and for the non-oil based route to chemicals production. Ceramic membranes are used to produce oxygen from air. Electrochemical energy conversion is another focused research area covering a number of technological areas: anode materials for lithium-ion batteries, catalysts and polymer electrolyte membranes for direct alcohols fuel cells, and materials for supercapacitors.

Materials for optoelectronic applications

Many optical devices based on 3D photonic crystals, such as optical switches, low-threshold lasers and light-emitting diodes, and waveguide, require the exact placement of artificial defects embedded in the interior of the photonic crystals. We have recently embedded artificial line-defects in a 3D photonic crystal using a combination of “bottom-up” self-assembly method and the conventional “top-down” technique. The new technique circumvents some of the problems in the self-assembly approach to fabricating functional photonic devices from photonic crystals.

Polymer and molecular electronics

Molecular memories based on polymers and organic materials have the advantages of simplicity in structure, drive-free read and write capability, good scalability, 3-D stacking ability, low-cost potential, and a large capacity for data storage. By combining molecular design with novel synthesis approaches, several polymer/molecular memories, including flash (rewritable) memory, write-once read-many-times (WORM) memory and dynamic random access memory (DRAM) have been realized. All these devices exhibit stable states with high ON/OFF current ratios (104-107), and perform up to 108 read cycles under ambient conditions.

Self-assembly of nanomaterials

A real-world functional material (e.g. solid catalyst) is a highly organized multi-component materials system. This modern view calls for the development of new strategies promoting the self-assembly of various functional components. For example, catalytic metals such as Au and Co can be introduced to the exterior surfaces or interior spaces of photosensitized metal oxide systems to enhance their functions as preparative nano-reactors. In another development colloidal and interfacial polymerizations are used to produce hydrophilic-lipophilic polymer composite membranes for separation; and micro-spheres and porous continuous media for catalyst immobilization and storage of energetic materials.

reference : http://www.chbe.nus.edu.sg/research/materials#


برچسب ها: materials، polymers، material، nanomaterials، nano،

تاریخ : شنبه 11 دی 1395 | 05:47 ب.ظ | نویسنده : Arash Sadeghi | نظرات

New building materials for the future of construction



نتیجه تصویری برای ‪future materials‬‏


Graphene

 

While not a new material, graphene has been impractical to use in construction since its discovery. In theory, it is an excellent building material, as it is incredibly lightweight while being stronger and stiffer than both steel and carbon fibre. Potentially, it could be combined with more traditional materials to create stronger beams and cables, allowing for more impressive structures.

 

However, graphene is so difficult to produce that builders have rarely been able to use more than a few flakes of it per project. Until now, that is, as the US' Oak Ridge National Laboratory has developed a new way of producing it using a technique known as chemical vapour deposition.

 

Ivan Vlassiouk, leader of the team responsible for the project, said that this discovery "considerably extends the potential applications and market for graphene". The next step is to reduce the cost and improve scalability, then the material can be used much more widely.

 

 

 

Natural concrete

 

Staying on the concrete theme, researchers from MIT have published a paper that proposes taking cement out of the equation altogether. The researchers, from the university's Department of Civil and Environmental Engineering, are looking to the natural world - proposing the use of organic materials like bones, shells and sea sponges to bind the aggregate in concrete together. 

 

The research is a fresh attempt to solve the twin drawbacks of Portland cement - the energy needed to make it, and the potential for microcracking over time. The idea came about when the team contrasted the extensive knowledge on the structure of natural materials with the 'guesswork' on concrete's internal structure - so it made sense to use more familiar materials in a 'bottom-up' approach to concrete production. 'Bone-crete' is not a material ready to be used just yet - it is more of a starting point for engineers to change the way they choose the composition of building products. 



Carbon-fibre balsa

 


Balsa wood is useful thanks to its stiffness despite being incredibly lightweight; however, it is difficult to produce and therefore expensive. However, a team of researchers at Harvard University have managed to create cellular composite materials of unprecedented light weight and stiffness that could replace it.

 

Fibre-reinforced epoxy-based thermosetting resins and 3D extrusion printing techniques have been used to create the synthetic replacement. The researchers used these methods to create a 'honeycomb' effect in carbon-fibre epoxy materials.

 

The end result is something that could potentially completely replace balsa wood. Not only would it be cheaper, it also eliminates the problems the wood has with irregular grains that make it difficult to use in precision structures.


Improved wood

 

Research from the Universities of Warwick and Cambridge has led to new understanding of the molecular structure of wood. This could lead to new uses for plants in construction, as well as an improved version of one of the most common building materials in the world.

 

The scientists found that the xylan polymer - which makes up about a third of wood's structure - has an unusual shape. This enabled them to study how molecules and cells within plant walls are arranged.

 

Professor Paul Dupree of the University of Cambridge said: "This major step forward in understanding the molecular architecture of plant cell walls will impact the use of plants for renewable materials, energy and for building construction."




طبقه بندی: اخبار پلیمری،
برچسب ها: polymers، construction، Graphene، wood، materials،

تاریخ : سه شنبه 7 دی 1395 | 12:49 ق.ظ | نویسنده : Arash Sadeghi | نظرات
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