Name: cooling rate dependent ellipsometry measurements to determine the dynamics of thin glassy films
Uploaded: 2016-01-26T18:00:00
Description: Watch this Scientific Journal Video about Cooling Rate Dependent Ellipsometry Measurements to Determine the Dynamics of Thin Glassy Films at JoVE.com

Forfatterne vil gerne anerkende James A. Forrest om hjælp i den indledende idé til denne teknik. 26. Dette arbejde blev støttet af midler fra University of Pennsylvania og blev delvist støttet af MRSEC program for National Science Foundation under award nej. DMR-11- 20901 ved University of Pennsylvania.

1. Film Forberedelse <ol><li> 0,04 g af polystyren afvejes og anbringes i en 30 ml hætteglas. </li><li> 2 g toluen afvejes i hætteglasset. En 2 vægt-% opløsning af polystyren i toluen giver en film på ca. 100 nm. </li><li> Lad opløsningen sidde O / N til fuldt ud at opløse polystyren og lad løsningerne bundfælde sig. </li><li> Placer en 1 cm x 1 cm Silicium (Si) wafer på en Spin Coater. </li><li> Spin skiven ved 8.000 rpm i 45 sek. Selv om det er spinning, drop ca. 1 ml toluen på spinning wafer. Bem?...

<ol>
	<li>Keddie, J. L., Jones, R. A. L., Cory, R. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Size-Dependent+depression+of+the+glass+transition+temperature+in+polymer+films.">Size-Dependent depression of the glass transition temperature in polymer films.</a> Europhys. Lett. 27 (1), 59-64 (1994).</li><li>Forrest, J. A., Veress, K. D., Dutcher, J. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Interface+and+chain+confinement+effects+on+the+glass+transition+temperature+of+thin+polymer+films.">Interface and chain confinement effects on the glass transition temperature of thin polymer films.</a> Phys. Rev.E. 56 (5), 5705-5716 (1997).</li><li>Forrest, J. A., Mattsson, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Reductions+of+the+glass+transition+temperature+in+thin+polymer+films:+Probing+the+length+scale+of+cooperative+dynamics.">Reductions of the glass transition temperature in thin polymer films: Probing the length scale of cooperative dynamics.</a> Phys. Rev.E. 61 (1), R53-R56 (2000).</li><li>Sharp, J. S., Forrest, J. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Free+surfaces+cause+reductions+in+the+glass+transition+temperature+of+thin+polystyrene+films.">Free surfaces cause reductions in the glass transition temperature of thin polystyrene films.</a> PRL. 91 (23), 235701 (2003).</li><li>Ellison, C. J., Torkelson, J. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+distribution+of+glass-transition+temperatures+in+nanoscopically+confined+glass+formers.">The distribution of glass-transition temperatures in nanoscopically confined glass formers.</a> Nat. Mat. 2 (10), 695-700 (2003).</li><li>Priestley, R. D., Ellison, C. J., Broadbelt, L. J., Torkelson, J. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Structural+relaxation+of+polymer+glasses+at+surfaces,+interfaces,+and+in+between.">Structural relaxation of polymer glasses at surfaces, interfaces, and in between.</a> Science. 309 (5733), 456-459 (2005).</li><li>Ellison, C. J., Kim, S. D., Hall, D. B., Torkelson, J. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Confinement+and+processing+effects+on+glass+transition+temperature+and+physical+aging+in+ultrathin+polymer+films:+Novel+fluorescence+measurements.">Confinement and processing effects on glass transition temperature and physical aging in ultrathin polymer films: Novel fluorescence measurements.</a> Euro. Phys. J. E. 8 (2), 155-166 (2002).</li><li>Ellison, C. J., Mundra, M. K., Torkelson, J. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Impacts+of+polystyrene+molecular+weight+and+modification+to+the+repeat+unit+structure+on+the+glass+Transition&#8722;Nanoconfinement+effect+and+the+cooperativity+length+scale.">Impacts of polystyrene molecular weight and modification to the repeat unit structure on the glass Transition&#8722;Nanoconfinement effect and the cooperativity length scale.</a> Macromolecules. 38 (5), 1767-1778 (2005).</li><li>Yang, Z., Fujii, Y., Lee, F. K., Lam, C. H., Tsui, O. K. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Glass+transition+dynamics+and+surface+layer+mobility+in+unentangled+polystyrene+films.">Glass transition dynamics and surface layer mobility in unentangled polystyrene films.</a> Science. 328 (5986), 1676-1679 (2010).</li><li>Tsui, O. K. C., Zhang, H. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effects+of+chain+ends+and+chain+entanglement+on+the+glass+transition+temperature+of+polymer+thin+films.">Effects of chain ends and chain entanglement on the glass transition temperature of polymer thin films.</a> Macromolecules. 34 (26), 9139-9142 (2001).</li><li>Roth, C. B., Dutcher, J. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Glass+Transition+and+Chain+Mobility+in+thin+Polymer+Films.">Glass Transition and Chain Mobility in thin Polymer Films.</a> J. Electroanal. Chem. 584, 13-22 (2005).</li><li>Ediger, M. D., Forrest, J. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Dynamics+near+Free+Surfaces+and+the+Glass+Transition+in+Thin+Polymer+Films:+A+View+to+the+Future.">Dynamics near Free Surfaces and the Glass Transition in Thin Polymer Films: A View to the Future.</a> Macromolecules. 47 (2), 471-478 (2014).</li><li>Serghei, A., Huth, H., Schick, C., Kremer, F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Glassy+dynamics+in+thin+polymer+layers+having+a+free+upper+interface.">Glassy dynamics in thin polymer layers having a free upper interface.</a> Macromolecules. 41 (10), 3636-3639 (2008).</li><li>Huth, H., Minakov, A. A., Schick, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Differential+AC-chip+calorimeter+for+glass+transition+measurements+in+ultrathin+films.">Differential AC-chip calorimeter for glass transition measurements in ultrathin films.</a> J. Polym. Sci. B. 44 (20), 2996-3005 (2006).</li><li>Tress, M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Glassy+dynamics+in+condensed+isolated+polymer+chains.">Glassy dynamics in condensed isolated polymer chains.</a> Science. 341 (6152), 1371-1374 (2013).</li><li>Boucher, V. M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=T+g+depression+and+invariant+segmental+dynamics+in+polystyrene+thin+films.">T g depression and invariant segmental dynamics in polystyrene thin films.</a> Soft Matter. 8 (19), 5119-5122 (2012).</li><li>Yu, M., Olson, E. A., Zhang, M., Zhang, Z., Allen, L. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Glass+transition+in+ultrathin+polymer+films:+Calorimetric+study.">Glass transition in ultrathin polymer films: Calorimetric study.</a> PRL. 91 (8), 085703 (2003).</li><li>Kremer, F., Tress, M., Mapesa, E. U. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Glassy+dynamics+and+glass+transition+in+nanometric+layers+and+films:+A+silver+lining+on+the+horizon.">Glassy dynamics and glass transition in nanometric layers and films: A silver lining on the horizon.</a> J. Non-Crys. Solids. 407, 277-283 (2015).</li><li>Qi, D., Ilton, M., Forrest, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Measuring+surface+and+bulk+relaxation+in+glassy+polymers.">Measuring surface and bulk relaxation in glassy polymers.</a> Euro. Phys. J. E. 34 (6), 1-7 (2011).</li><li>Teichroeb, J. H., Forrest, J. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Direct+imaging+of+nanoparticle+embedding+to+probe+viscoelasticity+of+polymer+surfaces.">Direct imaging of nanoparticle embedding to probe viscoelasticity of polymer surfaces.</a> PRL. 91 (1), 016104 (2003).</li><li>Fakhraai, Z., Forrest, J. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Measuring+the+surface+dynamics+of+glassy+polymers.">Measuring the surface dynamics of glassy polymers.</a> Science. 319 (5863), 600-604 (2008).</li><li>Paeng, K., Swallen, S. F., Ediger, M. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Direct+measurement+of+molecular+motion+in+freestanding+polystyrene+thin+films.">Direct measurement of molecular motion in freestanding polystyrene thin films.</a> J. Am. Chem. Soc. 133 (22), 8444-8447 (2011).</li><li>Glor, E. C., Fakhraai, Z. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Facilitation+of+interfacial+dynamics+in+entagled+polymer+films.">Facilitation of interfacial dynamics in entagled polymer films.</a> JCP. 141 (9), 194505 (2014).</li><li>Fakhraai, Z., Forrest, J. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Probing+slow+dynamics+in+supported+thin+polymer+films.">Probing slow dynamics in supported thin polymer films.</a> PRL. 95 (2), 025701 (2005).</li><li>Roth, C. B., McNerny, K. L., Jager, W. F., Torkelson, J. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Eliminating+the+enhanced+mobility+at+the+free+surface+of+polystyrene:+fluorescence+studies+of+the+glass+transition+temperature+in+thin+bilayer+films+of+immiscible+polymers.">Eliminating the enhanced mobility at the free surface of polystyrene: fluorescence studies of the glass transition temperature in thin bilayer films of immiscible polymers.</a> Macromolecules. 40 (7), 2568-2574 (2007).</li><li>Priestley, R. D., Ellison, C. J., Broadbelt, L. J., Torkelson, J. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Structural+relaxation+of+polymer+glasses+at+surfaces,+interfaces,+and+in+between.">Structural relaxation of polymer glasses at surfaces, interfaces, and in between.</a> Science. 309 (5733), 456-459 (2005).</li><li>Gao, S., Koh, Y. P., Simon, S. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Calorimetric+Glass+Transition+of+Single+Polystyrene+Ultrathin+Films.">Calorimetric Glass Transition of Single Polystyrene Ultrathin Films.</a> Macromolecules. 46 (92), 562-570 (2013).</li><li>Tropin, T. V., Schulz, G., Schmelzer, J. W. P., Schick, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Heat+capacity+measurements+and+modeling+of+polystyrene+glass+transition+in+a+wide+range+of+cooling+rates.">Heat capacity measurements and modeling of polystyrene glass transition in a wide range of cooling rates.</a> J. Non-Cryst. Solids. 409, 63-75 (2015).</li><li>Kim, S., Hewlett, S. A., Roth, C. B., Torkelson, J. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Confinement+effects+of+glass+transition+temperature,+transition+breadth,+and+expansivity:+Comparison+of+ellipsometry+and+fluorescence+measurements+on+polystyrene+films.">Confinement effects of glass transition temperature, transition breadth, and expansivity: Comparison of ellipsometry and fluorescence measurements on polystyrene films.</a> Eur. Phys. J.E. 30, 83-92 (2009).</li><li>Schawe, J. E. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Vitrification+in+a+wide+cooling+rate+range:+The+relations+between+cooling+rate,+relaxation+time,+transition+width+and+fragility.">Vitrification in a wide cooling rate range: The relations between cooling rate, relaxation time, transition width and fragility.</a> JCP. 141, 184905 (2014).</li><li>Donth, E., Korus, J., Hempel, E., Beiner, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Comparison+of+DSC+heating+rate+and+HCS+frequency+at+the+glass+transition.">Comparison of DSC heating rate and HCS frequency at the glass transition.</a> Thermochimica Acta. 304-305, 239-249 (1997).</li><li>Zhang, C., Guo, Y., Priestley, R. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Confined+glassy+properties+of+polymer+nanoparticles.">Confined glassy properties of polymer nanoparticles.</a> J. Polym. Sci. B. 51 (7), 574-586 (2013).</li><li>Koh, Y. P., Grassia, L., Simon, S. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Structural+Recovery+of+a+Single+Polystyrene+Thin+Film+Using+Nanocalorimetry+to+Extend+the+Aging+Time+and+Temperature+Range.">Structural Recovery of a Single Polystyrene Thin Film Using Nanocalorimetry to Extend the Aging Time and Temperature Range.</a> Thermochimica Acta. 603, 135-141 (2015).</li><li>Gao, S., Simon, S. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Measurement+of+the+limiting+fictive+temperature+over+five+decades+of+cooling+and+heating+rates.">Measurement of the limiting fictive temperature over five decades of cooling and heating rates.</a> Thermochimica Acta. 603, 123-127 (2015).</li></ol>

Køling-Rate afhængig T g målinger er højt gennemløb karakterisering eksperimenter, der kan bestemme Tg, udvidelseskoefficienten af glasset og super-afkølet væske, temperaturafhængighed af den gennemsnitlige dynamik og skrøbelighed af en bestemt glasagtigt materiale i et enkelt eksperiment. Til forskel fluorescens, indlejring eller nanohole afslapning eksperimenter, CR-T g eksperimenter er relativt hurtig og enkel, fordi de ikke udnytter fluorophorer eller andre komplicerede eksp...

Den skelsættende arbejde Keddie Jones og Corey 1 viste, at glasovergangstemperaturen (Tg) af ultratynde polystyrenfilm falder i forhold til hovedparten værdi ved tykkelser mindre end 60 nm. Lige siden, har mange eksperimentelle undersøgelser 2-11 støttet hypotesen om, at de observerede reduktioner i Tg er forårsaget af et lag af øget mobilitet nær den frie overflade af disse film. Men disse eksperimenter er indirekte mål for en enkelt afslapning tid, og der er således en debat 12- 18 centreret om en direkte sammenhæng mellem de gennemsnitlige tyndfilm dynamik og dynamikken på luft / polymer-grænsefladen. For at besvare denne debat, har mange undersøgelser måles direkte dynamikken i den frie overflade (τ overflade). Nanopartikel indlejring, 19,20 nanohole afslapning, 21 og fluorescens 22 undersøgelser viser, at luft / polymer grænsefladen hsom dynamik størrelsesordener hurtigere end hovedparten alfa afslapning tid (τ α) med en meget svagere temperatur afhængighed end τ α. På grund af sin svage temperaturafhængighed, at τ overfladen af disse film, 19-22 og forbedrede dynamik tynde polystyrenfilm, 23,24 skærer hovedparten alfa afslapning (τ a) på et enkelt punkt T *, som er et par grader over Tg, og ved en τ α ≈ af 1 sek. Tilstedeværelsen af T * kunne forklare, hvorfor forsøg, som probe afslapning gange hurtigere end * ikke se nogen tykkelse afhængighed af Tg ultratynde polystyrenfilm. 13-18 Endelig mens direkte målinger af den forbedrede mobile fase viser, at den har en tykkelse på 4-8 nm, 20-22 er der bevis for, at udbredelseslængde af dynamikken ved luft / polymer-grænsefladen er meget større end tykkelsen af den mobile overflade Layer. 5,25,26 Denne rapport har til formål at fuldt beskrive en protokol for brug af ellipsometri til køling sats afhængig T g (CR-T g) eksperimenter. CR-Tg er tidligere blevet brugt til at beskrive de gennemsnitlige dynamik ultra-tynde film af polystyren. 23,24,27,28 Endvidere blev Denne teknik nylig bruges til at vise en direkte sammenhæng mellem de gennemsnitlige dynamik i ultratynde polystyren-film og dynamikken på den frie overflade. 23 Fordelen ved CR-T g målinger over andre typer målinger, såsom fluorescens, nanopartikel indlejring, nanohole afslapning, nanocalorimetry, dielektrisk spektroskopi og Brillouin lysspredning undersøgelser er, at de er relativt hurtig og simple eksperimenter, der ikke udnytter fluorophorer eller andre komplicerede eksperimentelle teknikker. Nylige fremskridt i spektroskopisk ellipsometri at denne teknik kan anvendes til effektivt at bestemme den optiske properterne af ultra-tynde film af polymerer og andre typer af hybride materialer med enestående præcision. Som sådan, denne teknik sonder de gennemsnitlige dynamik teknologisk gældende tynde film i temperatur og tid regimer relevante for glasovergangen (T ≤ Tg, τ α ≥ 100 sek). Desuden vil denne teknik give oplysninger om ekspansionskoefficienter af glasagtig og aftensmad afkølet flydende stater samt skrøbelighed af systemet, som derefter kan sammenlignes med data for bulk-film. Endelig kan CR- T g eksperimenter anvendes til enhver glasagtige system, så længe integriteten af filmen forbliver under hele forsøget.

<table border="0" cellpadding="0" cellspacing="0" width="918">
	<tbody>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Toluene</td>
			<td style="width:111px;">Sigma Aldrich</td>
			<td style="width:119px;">179418-1L</td>
			<td style="width:472px;">This can be purchased from any chemical company.</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">Atactic Polystyrene</td>
			<td style="width:111px;">Polymer Source Inc.</td>
			<td style="width:119px;">P-4092-S</td>
			<td>This can be purchased from any chemical company.</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">THMS 600 temperature stage</td>
			<td style="width:111px;">Linkam</td>
			<td style="width:119px;">THMS 600</td>
			<td>any temperature stage that can be fit to an ellipsometer could be used.</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">M2000V Spectroscopic Ellipsometer</td>
			<td style="width:111px;">J.A. Woollam</td>
			<td style="width:119px;">M200V</td>
			<td>This procedure should be applicable for any spectroscopic ellipsometer.</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">Spin Coater</td>
			<td style="width:111px;">Laurell Technologies</td>
			<td style="width:119px;">WS-650-23B</td>
			<td>This Procedure is possible with any spin coater</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Sample vials</td>
			<td style="width:111px;">Fisher Scientific</td>
			<td style="width:119px;">02-912-379</td>
			<td>Any sample vials will do</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">Silicon wafers</td>
			<td style="width:111px;">Virginia semi conductors</td>
			<td style="width:119px;">325S1410694D</td>
			<td></td>
		</tr>
	</tbody>
</table>

cooling rate dependent ellipsometry measurements to determine the dynamics of thin glassy films

Denne rapport har til formål at fuldt beskrive eksperimentelle teknik for at bruge ellipsometri til køling sats afhængig T g (CR-T g) eksperimenter. Disse målinger er enkle high-throughput karakteriseringsforsøg, der kan afgøre glasovergangstemperaturen (Tg), gennemsnitlige dynamik, skrøbelighed og udvidelsen koefficient af de super-kølet flydende og glastilstande for en række forskellige glasagtige materialer. Denne teknik giver mulighed for disse parametre, der skal måles i et enkelt forsøg, mens andre metoder skal kombinere en række forskellige teknikker til at undersøge alle disse egenskaber. Målinger af dynamik tæt på Tg er særligt udfordrende. Fordelen ved afkølingshastighed afhængig T g målinger over andre metoder, som direkte probe bulk- og overfladen afslapning dynamik er, at de er relativt hurtige og simple eksperimenter, som ikke udnytter fluorophorer eller andre komplicerede extelle teknikker. Desuden er denne teknik sonder de gennemsnitlige dynamik teknologisk relevante tynde film i temperatur og afslapning tid (τ α) systemer, som vedrører glasset overgang (τ α&gt; 100 sek). Begrænsningen at bruge ellipsometri til afkølingshastighed afhængig T g eksperimenter er, at det ikke kan undersøge relaksationstider er relevante for målinger af viskositeten (τ α &lt;&lt; 1 sek). Andre afkølingshastighed afhængig T g måleteknikker kan imidlertid udvide CR-Tg metode til hurtigere relaksationstider. Endvidere kan denne teknik anvendes til enhver glasagtige system, så længe integriteten af ​​filmen forbliver under hele forsøget.

Montering Raw Ellipsometri data Polystyren film er gennemsigtig i bølgelængdeområdet på ellipsometer (500-1,600 nm). Således vil en Cauchy model er en god model til at beskrive brydningsindeks polystyrenfilm. Figur 1A viser et eksempel på Ψ (λ) og Δ (λ) for en tyk (274 nm) film af polystyren, og den resulterende egnet til Cauchy-model <img alt="Ligning 1" src="/files/ftp_upload/53499...

Watch this Scientific Journal Video about Cooling Rate Dependent Ellipsometry Measurements to Determine the Dynamics of Thin Glassy Films at JoVE.com

Cooling Rate Dependent Ellipsometry Measurements to Determine the Dynamics of Thin Glassy Films

Her præsenteres en protokol for afkølingshastighed afhængige ellipsometri eksperimenter, der kan bestemme glasovergangstemperaturen (Tg), gennemsnitlige dynamik, skrøbelighed og udvidelseskoefficient af den super-afkølet væske og glas til en række glasagtige materialer.

Køling Rate Afhængige ellipsometri Målinger Bestem dynamikken i Thin Glassy Films

This report aims to fully describe the experimental technique of using ellipsometry for cooling rate dependent Tg (CR-Tg) experiments. These measurements ...

Research

JoVE Journal

Chemistry

Thin-layer Chromatographic (TLC) Separations and Bioassays of Plant Extracts to Identify Antimicrobial Compounds

Thin-layer Chromatographic TLC Separations and Bioassays of Plant Extracts to Identify Antimicrobial Compounds

Tyndtlagskromatografisk (TLC) Separations og Bioassays planteekstrakter til at identificere antimikrobielle forbindelser

A common screen for plant antimicrobial compounds consists of separating plant extracts by paper or thin-layer chromatography (PC or TLC), exposing the ...

Atomically Defined Templates for Epitaxial Growth of Complex Oxide Thin Films

Atomically skabeloner til epitaksial vækst af komplekse Oxide Thin Films

Atomically defined substrate surfaces are prerequisite for the epitaxial growth of complex oxide thin films. In this protocol, two approaches to obtain ...

High Precision Zinc Isotopic Measurements Applied to Mouse Organs

High Precision Zink Isotopiske Målinger Anvendt til Mouse organer

We present a procedure to measure with high precision zinc isotope ratios in mouse organs. Zinc is composed of 5 stable isotopes (64Zn, 66Zn, 67Zn, 68Zn ...

Fabrication of Large-area Free-standing Ultrathin Polymer Films

Fremstilling af Large-area Fritstående Ultratynde Polymer Films

This procedure describes a method for the fabrication of large-area and ultrathin free-standing polymer films.  Typically, ultrathin films are prepared ...

Unraveling Entropic Rate Acceleration Induced by Solvent Dynamics in Membrane Enzymes

Optrevling Entropiske Rate Acceleration induceret af Solvent Dynamics i Membrane Enzymer

Enzyme catalysis evolved in an aqueous environment. The influence of solvent dynamics on catalysis is, however, currently poorly understood and usually ...

Dissolution Dynamic Nuclear Polarization Instrumentation for Real-time Enzymatic Reaction Rate Measurements by NMR

Opløsning Dynamic Nuclear Polarisering Instrumentation for Real-time enzymatisk reaktion Rate Målinger ved NMR

The main limitation of NMR-based investigations is low sensitivity. This prompts for long acquisition times, thus preventing real-time NMR measurements of ...

Capillary Electrophoresis to Monitor Peptide Grafting onto Chitosan Films in Real Time

Kapillarelektroforese til Monitor peptid podning på Chitosan Film i Real Time

Free-solution capillary electrophoresis (CE) separates analytes, generally charged compounds in solution through the application of an electric field. ...

Electrochemical Impedance Spectroscopy as a Tool for Electrochemical Rate Constant Estimation

Elektrokemiske impedans spektroskopi som et redskab for elektrokemisk sats konstant estimering

Electrochemical impedance spectroscopy (EIS) was used for advanced characterization of organic electroactive compounds along with cyclic voltammetry (CV). ...

Reactive Vapor Deposition of Conjugated Polymer Films on Arbitrary Substrates

Reaktiv dampudfældning konjugeret Polymer film på vilkårlige substrater

We demonstrate a method of conformally coating conjugated polymers on arbitrary substrates using a custom-designed, low-pressure reaction chamber. ...

Solution-Processed "Silver-Bismuth-Iodine" Ternary Thin Films for Lead-Free Photovoltaic Absorbers

Løsning-forarbejdede "Sølv-Bismuth-jod" ternære tynde film for blyfri solcelleenergi absorptionsflaskerne

Bismuth-based hybrid perovskites are regarded as promising photo-active semiconductors for environment-friendly and air-stable solar cell applications. ...