CMDITR Review of Undergraduate Research - Pluto - University of ...

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heated bath. The glass test tube holding the monomer is slowly lowered into the heated bath at a constant speed ranging from 10 to 15 microns per second depending on whether or not there was any dopant, and what kind of dopant. This was setup so the preform would be lowered down into the bath gradually, allowing enough time for the submerged monomer to polymerize at a constant rate. The fiber-drawing tower has a motor that can be set to move at very slow speeds, and this was used to lower the preform into the bath. The preform was lowered into the bath by tying it with string to a metal rod fixed to a platform already used for lowering preforms into the furnace. This was advantageous because LabView computer software controls the speedsensitive motor. For a set speed, the motor will continuously lower the preform into the bath. The setup for temperature monitoring was already in place in the draw tower, with an electronic reader available. A type K thermocouple was placed in the middle of the oil bath to monitor the temperature. Experimentally it was determined that polymerization occurs best at approximately 80°C. The speed at which the preform was lowered into the bath is variable depending on whether or not the monomer was doped, and if so, the type of dopant. The polymerization process involves three main steps: an initial PMMA-MMA interfacial gel, a fifteen minute pre-heat fully lowering method, submerged (to begin polymerization) in the heated bath, and the continuous lowering method. The dopants that were being tested were all dyes – quinacridone dendrimers (AO-IV-155, AO-IV-111) and Pyrene (C 16 H 10 ). Experimentally, MMA preforms polymerize well at speeds of 10-11 microns per second (3.6 – 4.0cm/hr). With the addition of a dye, however, polymerization occurs faster and in order to avoid excess bubbling, the speed at which the preform is lowered into the heated bath must be increased. Preforms doped with pyrene and AO-IV-111 dye polymerized exceptionally well at 12 microns per second. The AO-IV-155 preform, which was doped at 0.5 wt % and polymerized at 12 microns per second, experienced minor bubbling. After polymerization was complete, all of the preforms were heat treated at 110°C to finish the polymerization process, evaporate off any gases remaining, and smoothen the preforms. The glass mold was broken off, and the preforms were further heat treated at 90°C in a drying furnace for two weeks. 8 CMDITR Review of Undergraduate Research Vol. 1 No. 1 Summer 2004
Fiber cladding preparation In order for light to pass through an optical fiber, there must be total internal reflection. Total internal reflection is a phenomenon that occurs between two materials of differing indices of refraction, where a light signal is reflected away from the material with the lower index of refraction. Through this successive bouncing back and forth, a light signal is able to travel through a fiber. Polymer optical fiber is usually composed of three materials: the core material, cladding, and final layer coating. The core is the material through which the light moves. Surrounding the core is a material with a lower index of refraction than the core, called the cladding. Light that hits the core-cladding interface at an angle greater than the critical angle is reflected away from the cladding, and light is able to “bounce” through the fiber core. Two methods are used to prepare cladding. The first method is a cascaded draw in which the cast preform is inserted into cascaded acrylic tubes. The second method is one previously carried out by Peng et al 4 where a Teflon line was fixed in the center of a mold, with MMA polymerizing around it. The Teflon line was removed, and then dye-doped monomer was poured into the hole and subsequently polymerized. A line of Teflon was inserted into a 1” diameter test tube with a Teflon plug weight into the bottom of the tube. An initial amount of MMA was placed in the tube, and polymerized in a heated bath at 75°C. This attached the Teflon plug to the bottom of the tube. MMA monomer was poured in the tube, and the Teflon line was pulled through the center of a makeshift cap at the top of the tube. The tube and monomer underwent the same 15-minute preheat, and was slowly lowered into the heated bath (maintained at 75°C) at speeds of approximately 12 microns per second. Once MMA was fully polymerized, the Teflon line was easily pulled out. However, the process has still yet to be perfected. In future research of fabrication of cladding for fibers, it is recommended augmenting the speeds at which the Teflon-lined preform polymerize, so there is less bubble formation in the cladding. Much more attention should be paid to the diameter variation of the Teflon line, and efforts should be made to place Teflon line closer to the exact center of the tube. CMDITR Review of Undergraduate Research Vol. 1 No. 1 Summer 2004 9
Page 1 and 2: CMDITR Review of Undergraduate Rese
Page 3 and 4: Welcome to the premier issue of the
Page 5 and 6: Extended Abstracts Table of Content
Page 7: wt % THV 220A). The glass tube was
Page 11 and 12: Acknowledgements Brian Ratliff, Gra
Page 13 and 14: Figure 2. Synthesis of the dendrime
Page 15 and 16: Toward the Synthesis of a Magnetic
Page 17 and 18: Results and Discussion Synthesis of
Page 19 and 20: years, (13) decomposes into a yello
Page 21 and 22: References 1. (a) MacDiarmid, A.G.
Page 23 and 24: suggests that any effects of these
Page 25 and 26: Electrospinning of Piezoelectric Ma
Page 27 and 28: varies and is close to the critical
Page 29 and 30: Synthesis of Azaindoly-phenanthroli
Page 31 and 32: Experimental Physical Measurements.
Page 33 and 34: [60] fullerene enable close packing
Page 35 and 36: Crystallization. We attempted to cr
Page 37 and 38: number of solvents including aceton
Page 39 and 40: References 1. Dalton, L.R. 2003. No
Page 41 and 42: though the beads were moving becaus
Page 43 and 44: Feasibility of Hydroxy-Chalcone Lin
Page 45 and 46: absorbance is proportional to conce
Page 47 and 48: Results Linear Dichroism Metripol c
Page 49 and 50: Pararosaniline Xylene Cyanole FF Cr
Page 51 and 52: the source of the light emitted by
Page 53 and 54: Figure 6. UV and PL spectra of the
Page 55 and 56: Method The hybrid chromophore will
Page 57 and 58: Results The ligand was synthesized
Page 59 and 60:
Following the cooling down, the pro
Page 61 and 62:
Two-Photon Induced Free Radical Pol
Page 63:
Future Work When the results of the
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