Student Project Abstracts 2005 - Pluto - University of Washington

NOTHERNFigure 2. Polymer Host.Scheme 4. Functionalization of polyene chromophore.At this point synthesis was considered complete and chromophore17 was embedded in an anthracene functionalized polymethyl-methacrylate(PMMA) host polymer with a 25 wt.%loading density (figure 2). It was spin-cast to form a .75um filmon a glass substrate half coated with conducting indium-tin-oxide(ITO) (120nm) particularly designed to be optically transparentat telecommunications wavelengths (1.3um). Three sampleswere prepared by sputteringSynthesis of a Polyenea goldEOelectrodeChromophoreonto the top of theDenis Nothern, Jingdong Luo, Alex K.-Y. Jenpolymer At this film point such synthesis that was they considered were half complete over and the ITO and half overchromophore 17 was embedded in an anthracene functionalizedthe glass (figure 3). This allowed a voltage to be applied acrosspoly-methyl-methacrylate (PMMA) host polymer with a 25.88 .12wt.% loading density (figure 2). It was spin-cast to form athe electrode and the ITO layer and pole the O polymer. OCH 3 O OWhile the.75um film on a glass substrate half coated with conductingpoling indium-tin-oxide voltage (ITO) was (120nm) being particularly applied, designed current to be passing through theoptically transparent at telecommunications wavelengthspolymer (1.3um). Three was samples carefully were prepared monitored by sputtering for indications a gold of damage to theelectrode onto the top of the polymer film such that they were Fig. 2. Polymer Host.film. half over During the ITO heating, and half over the the current glass (figure was 3). recorded This overtime. Onceallowed a voltage to be applied across the electrode and the ITO layer and pole the polymer.poled, While the the poling r 33voltage value was was being measured applied, current via passing the through reflection the polymer technique was carefully[3] .monitored for indications of damage to the film. During heating, the current was recordedThe results can be seen in the following section.overtime. Once poled, the r 33 value was measured via the reflection technique [3] . The results canbe seen in the following section.Figure 3. Poling setup.Scheme 5. Functionalization of AJC-139 chromophoreRESULTSFig. 3. Poling setup.Figure 4. Current Vs. Time.Scheme 6. Functionalization of 2 nd polyene cromophore.Results:All the samples were exposed Figure to 3. the Poling poling voltage setup.and then heated at a rate of 5 C/sec starting at 50 C. Thecurrent through the polymer layer varies over time as thesample is heated (figure 4). This gives an indication of whenAll the samples were exposed to the poling voltage and thenthe T g is being approached as the current reaches a localheatedmaxima (orata minimarate ofin the5°C/seccase of polymerstartingbreakdownat 50°C.andThe current throughcurrent is able to jump directly from the gold to the ITO).the polymer With a 25 layer wt.% loading varies density, over poling time with as 100V/um the sample is heated (figureat 111 C the r 33 value was found to be as high as 44pm/V4). (Table This 1). This gives is nearly an double indication the value for of the when less efficient the T gis being approachedchromophores previously implemented in such a side-chainFig. 4. Current Vs. Time.as scheme. the current The high poling reaches temperature a local is an maxima indication that (or the a minima in the case ofside-chains formed and that the thermal stability of the systempolymer will be good. breakdown Additionally, the and very current low current is at able such high to jump temperatures directly (4.5 uA from at 160theC)indicates that there is little phase separation between the polymer and the chromophores, whichgoldis in agreementto the ITO).with expectations for a side-chain structure.With a 25 wt.% loading density, poling with 100V/um atSample Field (V/um) Temp ('C) Current (uA) r 33 (pm/V)111°C the #1 r 33value 100.00 was found 160 to be as high 4.5 as 44pm/V 42 (Table 1).This is nearly double the value for the less efficient chromophorespreviously implemented in such a side-chain scheme. The 6 high of 7poling temperature is an indication that the side-chains formedand that the thermal stability of the system will be good. Additionally,the very low current at such high temperatures (4.5 uAat 160°C) indicates that there is little phase separation betweenthe polymer and the chromophores, which is in agreement withexpectations for a side-chain structure.CMDITR Review of Undergraduate Research Vol. 2 No. 1 Summer 2005 97