10-09 :: September 2010
nanotimes Companies
W.S. Tan, R.E. Cohen, M.F. Rubner, S.A. Sukhish- vili from Massachusetts Institute of Technology, USA, presented with “Self Assembled Block-copo- lymer Nanocomposite Multilayer Thin Films for Reversible Temperature Triggered Responses” in session “Polymer Nanotech: Copolymer surfaces: Applications ”, an investigation of a block copolymer solution.
Thermo-mechanically responsive surfaces in aqueous environments are sought after for a variety of bio- logical and micro-fluidic applications. Electrostatic self assembly of an A-B-A triblock co-polymer with a suitable polyanion was used to create smart surface coatings with up to 500% fully reversible, tempera- ture dependent swelling from all aqueous processing. The dry thickness of the films can be easily con- trolled between 50nm-1um. Poly(2-(dimethylamino) ethyl methacrylate)-b-polypropylene oxide-b- poly(2- (dimethylamino)ethyl methacrylate) (PDMAEMA- PPO-PDMAEMA) was used as a dual pH and temperature responsive component and to create hydrophobic nano-domains within an electrostatical- ly bound matrix. Incorporation of stimuli responsive block copolymers into electrostatically assembled thin films requires special attention to be paid to the molecular configuration of the stimuli responsive block. Their work investigates the block copolymer solution configuration and correlates how different aggregation states affect the temperature response of thin films assembled from these polymers. De- tailed studies have uncovered key factors necessary to achieve high fidelity large extent yet fully reversi- ble temperature induced volume transitions of multi- layer thin films. The temperature dependent swelling of such thin films is applied to control membrane permeability. Further, such coatings can also be used
http://web.mit.edu/dmse/rubner/index.htm
M. Reimark from TranSiC, USA, spoke about “Efficient Power Transistors in Silicon Carbide for PV applications”.
Silicon carbide (SiC) semiconductor devices for high power are becoming more mature and are now com- mercially available. Schottky diodes have been on the market since a few years. SiC power transistors in the form of bipolar junction transistors (BJTs), JFETs and MOSFETs are this year reaching the commercial market. The interest is rapidly growing for SiC power devices in demanding power and high temperature applications. The BJT has market leading low con- duction losses, fast switching capability and very predictably operate, in normally-off mode, in a very wide load/temperature range. They are the natural choice as a successor for the commonly used silicon IGBT of today. Reimark‘s presentation showed how losses can be greatly reduced and temperature range increased while system mass and volume are significantly reduced by the use of SiC BJT devices. Current state of the art in active switching device performance with special emphasis on BJTs was reviewed in perspective of demanding applica- tions. The performance of the SiC BJT will be com- pares to Silicon bipolar and unipolar devices over a wide temperature interval.
http://www.transic.com/index.php/news/78
to be continued ...
47
for cell sheet engineering as well as selective small molecule binding and release.
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56 |
Page 57 |
Page 58 |
Page 59 |
Page 60 |
Page 61 |
Page 62 |
Page 63 |
Page 64 |
Page 65 |
Page 66 |
Page 67 |
Page 68 |
Page 69 |
Page 70 |
Page 71 |
Page 72 |
Page 73 |
Page 74 |
Page 75 |
Page 76 |
Page 77 |
Page 78 |
Page 79 |
Page 80 |
Page 81