Bu eser ABD ordusu araştırma ofisi grant W911NF-15-1-0414 altında tarafından desteklenmektedir.

1. ev yapımı Knudsen hücre hazırlanması
<ol><li>
Bileşenleri Knudsen hücre için hazırlamak
	<ol>
<li>Satınalma Flanşlı CF güç feedthrough (2.75" CF, 4 PIN Paslanmaz Çelik) temel. İki evreli bir çapı 1.30" çizgi ile onun çevresi arasındaki çapraz noktalarda feedthrough üzerinden delik.</li>
		<li>Bir cam tüp (0.315" dış çap (OD), 2.50" uzunluğu) hazırlayın.</li>
		<li>İnce bakır levhalar (% 99.9) 0.005" kalınlığı ile satın alabilirsiniz. Bir yaprak boyutlarında 7.5" L kesme x 5.0" bir çift makas, daha sonra içi boş bir columniform için kalkan bir 1.45" çapı ile el ile curl kullanarak W (Şekil 1a).</li>
		<li>0.005" çapında türü K ısıl (chromel/alumel) bir uzunluğu 3" chromel ve alumel telleri keserek hazırlayın. Peel yalıtkan katmanları yaklaşık 0,5" her iki uçtan her iki kablo uzunluğu.</li>
		<li>Bir 0,01" çapı tungsten kabloyu (%99,95) uzunluğu yaklaşık 60" için kesin. Bir bahar şekil çapında 0.315" sıkı bir şekilde cam tüp karşılaştırılabilir çapı bir çubuk sarma tarafından Kangal.</li>
		<li>Seramik bir parça satın. Tek uygun küboid parça cam (5'te Şekil 1b) boyut uygun orta delik hazırlayın.</li>
		<li>2 standart çelik dişli 0.10" çapı çubuklar bantlama ve testere ile bir Torna Makinesi 7" uzunluğa kekemelik.</li>
		<li>Makas kullanarak bir yaklaşık 30" uzunluğu için bir yumuşak, 0.01" çapı Bakır kabloyu kesin.</li>
		<li>4 içi boş bakır çubuklar 0,094" OD çapı 2" uzunluğunu ve yan kesici kullanarak bir 4" uzunluğu için bir çubuk için üç çubuklar keserek hazırlayın.</li>
	</ol>
</li>
	<li>
Knudsen hücredeki bu parçaları bir araya
	<ol>
<li>Adım 1.1 aseton 30 dk 42 kHz temizlik ultrasonik kullanarak belirtilen tüm bileşenleri temiz.</li>
		<li>2 standart çelik dişli çubuklar güç feedthrough CF flanş delinmiş deliklere monte. Not: Dişli (7 Şekil 1b) delikleri vardır.</li>
		<li>Alt Flanşlı CF güç feedthrough 4 PIN üst kısmında 4 içi boş bakır çubuklar yarısı PIN içi boş bakır çubuklar ekleyerek ve onları bir yan kesici (6'Şekil 1b) tarafından tamir montaj.</li>
		<li>Dişli çubuklar ile yumuşak bakır tel derinliklerinden gelen seramik parça 2,5" yüksek konumunda bağlayın. Not: Bu parça cam tüp Aşağıdaki adımda (5'te Şekil 1b) destekler.</li>
		<li>Cam tüp kıvrılmış tungsten bahar içine kaydırın. Cam tüp alt seramik parça deliğe sıkmak. Yumuşak bakır tel cam tüp üst kısmına dişli çubuklar (3 ve 4'te Şekil 1b) üst kısmına tutmak için kullanın.</li>
		<li>A. kavrama olarak bahar ucuna B (A ve B Şekil 1b) tanımlanan daha kısa bakır çubuklar, birinde tanımlanan uzun bakır çubuk içine bahar üst kısmına kavrama.</li>
		<li>Hem chromel hem de alumel teller birlikte (2'Şekil 1b) bir soyulmuş ucunu twist.</li>
		<li>Cam tüp dış alt yakından dokunana bükülmüş ortak sonuna konumlandırın. Seramik parça yardımıyla hareketsiz.</li>
		<li>Chromel diğer soyulmuş ucunu C. kavrama tanımlanan sol 2 Kısa bakır çubuklar, birinin içine soyulmuş öbür D (C ve D Şekil 1b) tanımlanan sol kısa bakır çubuk, içine alumel tel tel kavrama.</li>
		<li>Kıvrılmış bakır içi boş columniform kalkan Flanşlı CF güç feedthrough üzerinde (Şekil 1a) koymak.</li>
	</ol>
</li>
</ol>2. ev yapımı Knudsen hücre C60 kaynağında hazırlayın
<ol><li>C60 kaynak ev yapımı Knudsen hücredeki yüklemek.<ol>
<li>Yaklaşık 50 mg C60 tozu (%99,5 saflıkta) ev yapımı Knudsen hücre cam tüp içine yükleyin. Not: Hassas 1 mg toz kütlesi ötesinde gereksizdir.</li>
		<li>Knudsen hücre geri yükleme kilit bir dalı üzerine monte.</li>
	</ol>
</li>
	<li>Yük kilit pompa.<ol>
<li>Pompa için yük kilidi açın. İlk turbo pompa soğutma için su vanası açmak, sonra mekanik pompa soğutmak için fan dönün. Sonra mekanik pompa ve nihayet turbo pompa üzerinde açın.</li>
		<li>Yük kilit basıncı kontrol ve yaklaşık 10 saat bekleyin. Not: Turbo pompa çıkış basınçta 6.0 x 10-2 mbar olmalıdır.</li>
		<li>(Genellikle aşağıda 10-6 mbar) daha düşük bir basınç yükü kilit monte iyon ölçüm açın.</li>
		<li>Yük kilit basıncı kontrol: basınç 10 h pompalama sonra 10-8 mbar aralığında olmalıdır.</li>
	</ol>
</li>
	<li>Ev yapımı Knudsen hücre C60 kaynağında tavlamak.<ol>
<li>Ev yapımı Knudsen hücre C60 kaynağında yavaş yavaş tavlama (1,5 ° C/dak) tedarik bir güç bağlanarak gaz giderme için 2 h için 250 ° C'de Flanşlı CF güç feedthrough kıvrılmış tungsten bahar bağlı olan iki iğne.</li>
		<li>İfade sıcaklığı (270 ° C) 300 ° C tavlama sıcaklığı artırmak.</li>
		<li>Daha fazla gaz giderme için 0,5 h için 300 ° C'de tavlamak.</li>
		<li>İfade için 270 ° c sıcaklık azaltın.</li>
	</ol>
</li>
</ol>3. UHV odasında atomik temiz grafen hazırlayın
<ol><li>Grafin (bakır folyo) örnek depolama atlıkarınca STM sisteminin (hazırlama ve bir örnek ultra yüksek vakum altında tavlama için özel bir yer) ultra yüksek vakum Hazırlık odasında tavlama plaka aktarın.</li>
	<li>400 ° c sıcaklık yavaş yavaş artırarak grafen substrat düşük 10-10 mbar Hazırlık odası içinde temel bir basınçta tavlama</li>
	<li>Grafin yüzeyinde kalan kirleri çıkarmak 12 h bekleyin.</li>
	<li>Grafin substrat yavaş yavaş için oda sıcaklığında için tavlama sıcaklığı azaltın.</li>
</ol>4. mevduat Graphene yük kilit ev yapımı Knudsen hücreye kullanarak substrat üzerine C 60
<ol><li>Grafin substrat yük kilit aktarın.<ol>
<li>Transfer pozisyonda Hazırlık odasında plaka yerleştir. Atomik temiz grafen yük kilit için ifade C60, -den sonra having atomik temiz grafen ve C60 kaynak hazır aktarın.</li>
		<li>Yük kilidi ve Hazırlık odası arasında Vanayı aç.</li>
		<li>Hazırlık odasında plaka grafen substrat yük kilit loadout aracı ile aktarın.</li>
		<li>Grafin substrat yüzü aşağı (60 C kaynağından geliyor).</li>
	</ol>
</li>
	<li>Grafin substrat üzerine C60 Kasası. Not: 270 ° C'de grafen substrat ev yapımı Knudsen hücreden C60 molekülleri transfer<ol>
<li>Bir ifade oranı 0.9 monolayer/dk 1 dk bekleyin.</li>
		<li>C60/graphene örnek hazırlık odasına aktar.</li>
	</ol>
</li>
</ol>5. C 60 /Graphene örnek STM ana odasında ölçülecek hazırlayın
<ol><li>C60/graphene örnek 3.1 ° C/dk'ya ultra yüksek vakum Hazırlık odasında 2 h oranı 150 ° C'ye tavlamak.</li>
	<li>C60/graphene örnek STM STM ana odasında ile inceden inceye gözden geçirmek.</li>
	<li>C60/graphene örnek için 210 ° C 3.1 ° C/dk'ya 2 h hızıyla tavlamak.</li>
	<li>C60/graphene örnek STM ile inceden inceye gözden geçirmek.</li>
</ol>

<ol>
	<li>Gutzler, R., Heckl, W. M., Lackinger, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Combination+of+a+Knudsen+effusion+cell+with+a+quartz+crystal+microbalance:+In+situ+measurement+of+molecular+evaporation+rates+with+a+fully+functional+deposition+source.">Combination of a Knudsen effusion cell with a quartz crystal microbalance: In situ measurement of molecular evaporation rates with a fully functional deposition source.</a> Review of Scientific Instruments. 81, 015108 (2010).</li><li>de Barros, A. L. F., 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=A+simple+experimental+arrangement+for+measuring+the+vapour+pressures+and+sublimation+enthalpies+by+the+Knudsen+effusion+method:+Application+to+DNA+and+RNA+bases.">A simple experimental arrangement for measuring the vapour pressures and sublimation enthalpies by the Knudsen effusion method: Application to DNA and RNA bases.</a> Nuclear Instruments &amp; Methods in Physics Research Section a-Accelerators Spectrometers Detectors and Associated Equipment. 560, (2006).</li><li>Shukla, A. K., 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=Versatile+UHV+compatible+Knudsen+type+effusion+cell.">Versatile UHV compatible Knudsen type effusion cell.</a> Review of Scientific Instruments. 75, 4467 (2004).</li><li>Cho, J., 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=Structural+and+Electronic+Decoupling+of+C60+from+Epitaxial+Graphene+on+SiC.">Structural and Electronic Decoupling of C60 from Epitaxial Graphene on SiC.</a> Nano Letters. 12, 3018 (2012).</li><li>Jung, 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=Atomically+resolved+orientational+ordering+of+C60+molecules+on+epitaxial+graphene+on+Cu(111).">Atomically resolved orientational ordering of C60 molecules on epitaxial graphene on Cu(111).</a> Nanoscale. 6 (111), 11835 (2014).</li><li>Li, G., 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=Self-assembly+of+C60+monolayer+on+epitaxially+grown,+nanostructured+graphene+on+Ru(0001)+surface.">Self-assembly of C60 monolayer on epitaxially grown, nanostructured graphene on Ru(0001) surface.</a> Applied Physics Letters. 100 (0001), 013304 (2012).</li><li>Lu, J., 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=Using+the+Graphene+Moire+Pattern+for+the+Trapping+of+C60+and+Homoepitaxy+of+Graphene.">Using the Graphene Moire Pattern for the Trapping of C60 and Homoepitaxy of Graphene.</a> Acs Nano. 6, 944 (2012).</li><li>Zhou, H. T., 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=Direct+imaging+of+intrinsic+molecular+orbitals+using+two-dimensional,+epitaxially-grown,+nanostructured+graphene+for+study+of+single+molecule+and+interactions.">Direct imaging of intrinsic molecular orbitals using two-dimensional, epitaxially-grown, nanostructured graphene for study of single molecule and interactions.</a> Applied Physics Letters. 99, 153101 (2011).</li><li>Belaish, I., 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=Spin+Cast+Thin-Films+of+Fullerenes+and+Fluorinated+Fullerenes+-+Preparation+and+Characterization+by+X-Ray+Reflectivity+and+Surface+Diffuse-X-Ray+Scattering.">Spin Cast Thin-Films of Fullerenes and Fluorinated Fullerenes - Preparation and Characterization by X-Ray Reflectivity and Surface Diffuse-X-Ray Scattering.</a> Journal of Applied Physics. 71, 5248 (1992).</li><li>Bezmel'nitsyn, V. N., Eletskii, A. V., Okun', M. V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Fullerenes+in+solutions.">Fullerenes in solutions.</a> Uspekhi Fizicheskikh Nauk. 168, 1195 (1998).</li><li>Ma, D. N., Sandoval, S., Muralidharan, K., Raghavan, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effect+of+surface+preparation+of+copper+on+spin-coating+driven+self-assembly+of+fullerene+molecules.">Effect of surface preparation of copper on spin-coating driven self-assembly of fullerene molecules.</a> Microelectronic Engineering. 170, 8 (2017).</li><li>Chen, C. H., Zheng, H. S., Mills, A., Heflin, J. R., Tao, C. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Temperature+Evolution+of+Quasi-one-dimensional+C60+Nanostructures+on+Rippled+Graphene.">Temperature Evolution of Quasi-one-dimensional C60 Nanostructures on Rippled Graphene.</a> Scientific Reports. 5, 14336 (2015).</li></ol>

İfşa etmek yok.

Bu protokol için açıklanan teknikleri organik malzemeler ve diğer yüksek buhar basıncı malzemelerin termal ifade için tasarlanmıştır. Bu tekniklerin örnek hazırlama alanları moleküler buharlaşma hem de termal tavlama destekleme kapasitesine sahip olan ultra yüksek vakum sistemleri ile entegre edilebilir. Bu özel deneme için C60 molekülleri grafen substrat ve çalışma yatırmak için amaçtır kendinden montajlı, C60 ve termal etkisi.
Yöntemin yarar...

Bu iletişim kuralı, mevduat ve 1 D ve yarı - 1 D C60 zincir yapıları gerçekleştirilebilir öyle ki C60 molekülleri grafen üzerinde işlemek açıklar. Bu deney teknikleri yavaş ve büyük çaba gerektirebilir, manuel manipülasyon üzerinde güvenmek zorunda kalmadan arzu yapılandırmaları adsorbates rehberlik gereksinimi karşılamak için geliştirilmiştir. Burada açıklanan yordamları bir örnek hazırlama alanı moleküler ifade ve termal örnekleri tavlama destekleme kapasitesine sahip bir yüksek vakum sistemiyle kullanımı güveniyor. STM örnekleri tanımlamak için kullanılır, ancak diğer moleküler çözümleme teknikleri uygulanabilir.
Knudsen hücre içindeki moleküllerin termal buharlaşma ince filmler hazırlamak için verimli ve temiz bir yoldur. Bu protokol için bir Knudsen hücre C60 molekülleri grafen substrat üzerine buharlaşır için kullanılır. Bu Knudsen hücre Evaporatör esas olarak bir kuvars tüp, bir Isıtma filament, ısıl tel ve feedthroughs1,2,3oluşur. Kuvars tüp molekülleri barındırmak için kullanılır, kuvars molekülleri ile tüp tungsten filaman ısıtır geçerli uygulanan ve ısıl tel ısısını ölçmek için kullanılır. Deneylerde ifade oranı Knudsen hücre sıcaklık kaynağında ayarlama tarafından kontrol edilir. Isıl tel quartz tüpün dış duvarına bitişik ve bu nedenle genellikle moleküler kaynak olduğu hücre içinde sıcaklık biraz farklıdır dış duvar sıcaklığını ölçmek. Kuvars tüp tam sıcaklığı elde etmek için kalibrasyon sıcaklık iç ve dış tüp ölçmek için iki ısıl kurulumları kullanarak gerçekleştirilen ve sıcaklık farkı kaydedildi. Bu şekilde, biz daha doğrusu quartz tüpün dışına yapıştırılmış ısıl tel kullanarak moleküler buharlaşma deneyleri sırasında kaynak sıcaklığını denetleyebilirsiniz. Molekülleri buharlaşıp sublimated moleküllerinin küçük bir miktar daha düşük basınçta bir gaz halinde olan yakıtlar aşamasında çünkü, genellikle bir ilişkili basınç değişikliği olduğunu. Bu nedenle, yükü kilit içindeki basınç değişikliği dikkatlice izleyin.
Bu Evaporatör C60, Ga, Al ve Hg4,5,6,7,8C70, Bor subphthalocyanine klorür gibi çeşitli molekül kaynakları yatırmak için kullanılabilir. Ondan beri var hayır çözücü için gerekli diğer ince film hazırlama teknikleri ile karşılaştırıldığında, örneğin,9,10,11, termal buharlaşma yüksek vakum döküm spin çok temiz ve çok yönlü olduğunu Yeminli ifade. Ayrıca, gaz giderme işleminden önce ifade olası yabancı maddelerin ortadan kaldırarak kaynak, saflığı geliştirir.

<table>
	<tbody>
		<tr>
			<td>CF Flanged power feedthrough</td>
			<td>Kurt J. Lesker</td>
			<td>EFT0042033</td>
			<td></td>
		</tr>
		<tr>
			<td>Copper sheets</td>
			<td>Alfa Aesar</td>
			<td>7440-50-8</td>
			<td></td>
		</tr>
		<tr>
			<td>Thermocouple chromel/alumel wires</td>
			<td>Omega Engineering</td>
			<td>ST032034/ST080042</td>
			<td></td>
		</tr>
		<tr>
			<td>Tungsten wires</td>
			<td>Alfa Aesar</td>
			<td>7440-33-7</td>
			<td></td>
		</tr>
		<tr>
			<td>Stainless steel rods</td>
			<td>McMaster-Carr</td>
			<td>95412A868</td>
			<td></td>
		</tr>
		<tr>
			<td>Copper wires</td>
			<td>McMaster-Carr</td>
			<td>8873K28</td>
			<td></td>
		</tr>
		<tr>
			<td>Hollow copper rods</td>
			<td>McMaster-Carr</td>
			<td>7190K52</td>
			<td></td>
		</tr>
		<tr>
			<td>C60</td>
			<td>MER Corporation</td>
			<td>MR6LP</td>
			<td></td>
		</tr>
	</tbody>
</table>

preparation and characterization of c60/graphene hybrid nanostructures

Yüksek vakum ortamında fiziksel termal ifade grafen üzerinde yeni moleküler nanoyapıların imalatı için temiz ve kontrol edilebilir bir yöntemdir. Biz yatırma ve pasif sakinleştirmek grafen fark uygulamaları 1 D C60/graphene hibrid yapıları içeren peşinde ilerlemek C60 molekülleri işleme yöntemleri mevcut. Bu Fuarı olarak uygulanan teknikler hazırlama alanları moleküler ifade hem de termal örnekleri tavlama destekleme kapasitesine sahip olan yüksek vakum sistemleri doğru içindir. C60 ifade tarama tünelleme mikroskobu (STM) sisteme bağlı bir ev yapımı Knudsen hücre kullanarak düşük basınçta odaklanmak. Yatırılan moleküllerin sayısı Knudsen hücre ve ifade saat sıcaklığını kontrol ederek düzenlenmiştir. Tek boyutlu (1D) C60 zincir yapıları iki ya da üç moleküllerin GENIŞLIĞIYLE deneysel Koşulları ayarlama yoluyla hazırlanabilir. Tavlama sıcaklığı onları sakinleştirmek grafen periyodik potansiyel içinde taşımak izin ile C60 molekülleri yüzey hareketliliğini artırır. Bu mekanizmasını kullanarak, 1 D C60 zincir yapıları bir Altıgen yakın Paketli yarı - 1 D şerit yapısına geçiş kontrol etmek mümkündür.

Buharlaşma, 2s için 150 ° C'de grafen yeni yatırılan C60 ile komplementer olan. Şekil 2a büyük ölçekli STM görüntüde bu ilk tavlama işleminden sonra bulundu bir karakteristik yarı - 1 D C60 zincir yapısı gösterilmektedir. Şekil 2B daha yakından bir inceleme her parlak küresel çıkıntı bir tek C60 molekül temsil eden bu 1 D yapının detaylı bilgi ortaya koymaktadır. Bimo...

Watch this Scientific Journal Video about Preparation and Characterization of C60/Graphene Hybrid Nanostructures at JoVE.com

Preparation and Characterization of C60/Graphene Hybrid Nanostructures

C60/Graphene hibrid nanoyapıların malzemelerin hazırlık ve

Burada C60/graphene hibrid nanoyapıların imalatı için bir protokol tarafından fiziksel termal buharlaşma mevcut. Özellikle, ifade ve tavlama koşullarının uygun işleme izin 1D ve yarı 1 d C oluşturulması üzerinde kontrol60 yapıları üzerinde sakinleştirmek grafen.

Physical thermal deposition in a high vacuum environment is a clean and controllable method for fabricating novel molecular nanostructures on graphene. We ...

preparation-and-characterization-of-c60graphene-hybrid-nanostructures

Research

JoVE Journal

Chemistry

Preparation and Characterization of C60/Graphene Hybrid Nanostructures

9.4K Görüntüleme.  Virginia Tech. Burada C60/graphene hibrid nanoyapıların imalatı için bir protokol tarafından fiziksel termal buharlaşma mevcut. Özellikle, ifade ve tavlama koşullarının uygun işleme izin 1D ve yarı 1 d C oluşturulması üzerinde kontrol60 yapıları üzerinde sakinleştirmek grafen.

Video: Preparation and Characterization of C60/Graphene Hybrid Nanostructures

Gyroid Nickel Nanostructures from Diblock Copolymer Supramolecules

Nanoporous metal foams possess a unique combination of properties - they are catalytically active, thermally and electrically conductive, and furthermore, have high porosity, high surface-to-volume and strength-to-weight ratio. Unfortunately, common approaches for preparation of metallic nanostructures render materials with highly disordered architecture, which might have an adverse effect on their mechanical properties. Block copolymers have the ability to self-assemble into ordered nanostructures and can be applied as templates for the preparation of well-ordered metal nanofoams. Here we describe the application of a block copolymer-based supramolecular complex - polystyrene-block-poly(4-vinylpyridine)(pentadecylphenol) PS-b-P4VP(PDP) - as a precursor for well-ordered nickel nanofoam. The supramolecular complexes exhibit a phase behavior similar to conventional block copolymers and can self-assemble into the bicontinuous gyroid morphology with two PS networks placed in a P4VP(PDP) matrix. PDP can be dissolved in ethanol leading to the formation of a porous structure that can be backfilled with metal. Using electroless plating technique, nickel can be inserted into the template&#39;s channels. Finally, the remaining polymer can be removed via pyrolysis from the polymer/inorganic nanohybrid resulting in nanoporous nickel foam with inverse gyroid morphology.

This article describes the preparation of well-ordered nickel nanofoams via electroless metal deposition onto nanoporous templates obtained from self-assembled diblock copolymer based supramolecules.

Buradaki iki bloklu kopolimer Supramolecules ikinci Gyroid Nikel Nanoyapılar

Nanoporous metal foams possess a unique combination of properties - they are catalytically active, thermally and electrically conductive, and furthermore, ...

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Split-and-pool Synthesis and Characterization of Peptide Tertiary Amide Library

Peptidomimetics are great sources of protein ligands. The oligomeric nature of these compounds enables us to access large synthetic libraries on solid phase by using combinatorial chemistry. One of the most well studied classes of peptidomimetics is peptoids. Peptoids are easy to synthesize and have been shown to be proteolysis-resistant and cell-permeable. Over the past decade, many useful protein ligands have been identified through screening of peptoid libraries. However, most of the ligands identified from peptoid libraries do not display high affinity, with rare exceptions. This may be due, in part, to the lack of chiral centers and conformational constraints in peptoid molecules. Recently, we described a new synthetic route to access peptide tertiary amides (PTAs). PTAs are a superfamily of peptidomimetics that include but are not limited to peptides, peptoids and N-methylated peptides. With side chains on both &#945;-carbon and main chain nitrogen atoms, the conformation of these molecules are greatly constrained by sterical hindrance and allylic 1,3 strain. (Figure 1) Our study suggests that these PTA molecules are highly structured in solution and can be used to identify protein ligands. We believe that these molecules can be a future source of high-affinity protein ligands. Here we describe the synthetic method combining the power of both split-and-pool and sub-monomer strategies to synthesize a sample one-bead one-compound (OBOC) library of PTAs.

Peptide tertiary amides (PTAs) are a superfamily of peptidomimetics that include but are not limited to peptides, peptoids and N-methylated peptides. Here we describe a synthetic method which combines&#160;both split-and-pool and sub-monomer strategies to synthesize a one-bead one-compound library of PTAs.

Split-ve-havuz Sentezi ve Peptit Tersiyer Amid Kütüphanesi Karakterizasyonu

Peptidomimetics are great sources of protein ligands. The oligomeric nature of these compounds enables us to access large synthetic libraries on solid ...

Synthesis and Characterization of Functionalized Metal-organic Frameworks

Metal-organic frameworks have attracted extraordinary amounts of research attention, as they are attractive candidates for numerous industrial and technological applications. Their signature property is their ultrahigh porosity, which however imparts a series of challenges when it comes to both constructing them and working with them. Securing desired MOF chemical and physical functionality by linker/node assembly into a highly porous framework of choice can pose difficulties, as less porous and more thermodynamically stable congeners (e.g., other crystalline polymorphs, catenated analogues) are often preferentially obtained by conventional synthesis methods. Once the desired product is obtained, its characterization often requires specialized techniques that address complications potentially arising from, for example, guest-molecule loss or preferential orientation of microcrystallites. Finally, accessing the large voids inside the MOFs for use in applications that involve gases can be problematic, as frameworks may be subject to collapse during removal of solvent molecules (remnants of solvothermal synthesis). In this paper, we describe synthesis and characterization methods routinely utilized in our lab either to solve or circumvent these issues. The methods include solvent-assisted linker exchange, powder X-ray diffraction in capillaries, and materials activation (cavity evacuation) by supercritical CO2 drying. Finally, we provide a protocol for determining a suitable pressure region for applying the Brunauer-Emmett-Teller analysis to nitrogen isotherms, so as to estimate surface area of MOFs with good accuracy.

Synthesis, activation, and characterization of intentionally designed metal-organic framework materials is challenging, especially when building blocks are incompatible or unwanted polymorphs are thermodynamically favored over desired forms. We describe how applications of solvent-assisted linker exchange, powder X-ray diffraction in capillaries and activation via supercritical CO2 drying, can address some of these challenges.

Fonksiyonlu Sentezi ve Karakterizasyonu Metal-organik Altyapıları

Metal-organic frameworks have attracted extraordinary amounts of research attention, as they are attractive candidates for numerous industrial and ...

Preparation and Characterization of SDF-1&#945;-Chitosan-Dextran Sulfate Nanoparticles

Chitosan (CS) and dextran sulfate (DS) are charged polysaccharides (glycans), which form polyelectrolyte complex-based nanoparticles when mixed under appropriate conditions. The glycan nanoparticles are useful carriers for protein factors, which facilitate the in vivo delivery of the proteins and sustain their retention in the targeted tissue. The glycan polyelectrolyte complexes are also ideal for protein delivery, as the incorporation is carried out in aqueous solution, which reduces the likelihood of inactivation of the proteins. Proteins with a heparin-binding site adhere to dextran sulfate readily, and are, in turn, stabilized by the binding. These particles are also less inflammatory and toxic when delivered in vivo. In the protocol described below, SDF-1&#945; (Stromal cell-derived factor-1&#945;), a stem cell homing factor, is first mixed and incubated with dextran sulfate. Chitosan is added to the mixture to form polyelectrolyte complexes, followed by zinc sulfate to stabilize the complexes with zinc bridges. The resultant SDF-1&#945;-DS-CS particles are measured for size (diameter) and surface charge (zeta potential). The amount of the incorporated SDF-1&#945; is determined, followed by measurements of its in vitro release rate and its chemotactic activity in a particle-bound form.

The objective of this protocol is to incorporate SDF-1&#945;, a stem cell homing factor, into dextran sulfate-chitosan nanoparticles. The resultant particles are measured for their size and zeta potential, as well as the content, activity, and in vitro release rate of SDF-1&#945; from the nanoparticles.

SDF-1α-Kitosan-Dekstran Sülfat nano partiküllerin hazırlanması ve Karakterizasyonu

Chitosan (CS) and dextran sulfate (DS) are charged polysaccharides (glycans), which form polyelectrolyte complex-based nanoparticles when mixed under ...

Preparation and Characterization of Individual and Multi-drug Loaded Physically Entrapped Polymeric Micelles

Amphiphilic block copolymers like polyethyleneglycol-block-polylactic acid (PEG-b-PLA) can self-assemble into micelles above their critical micellar concentration forming hydrophobic cores surrounded by hydrophilic shells in aqueous environments. The core of these micelles can be utilized to load hydrophobic, poorly water soluble drugs like docetaxel (DTX) and everolimus (EVR). Systematic characterization of the micelle structure and drug loading capabilities are important before in vitro and in vivo studies can be conducted. The goal of the protocol described herein is to provide the necessary characterization steps to achieve standardized micellar products. DTX and EVR have intrinsic solubilities of 1.9 and 9.6 &#181;g/ml respectively Preparation of these micelles can be achieved through solvent casting which increases the aqueous solubility of DTX and EVR to 1.86 and 1.85 mg/ml, respectively. Drug stability in micelles evaluated at room temperature over 48 hr indicates that 97% or more of the drugs are retained in solution. Micelle size was assessed using dynamic light scattering and indicated that the size of these micelles was below 50 nm and depended on the molecular weight of the polymer. Drug release from the micelles was assessed using dialysis under sink conditions at pH 7.4 at 37 oC over 48 hr. Curve fitting results indicate that drug release is driven by a first order process indicating that it is diffusion driven.

The goal of this protocol is to describe the preparation and characterization of physically entrapped, poorly water soluble drugs in micellar drug delivery systems composed of amphiphilic block copolymers.

Hazırlanması ve Bireysel Karakterizasyonu ve Multi-ilaç Fiziksel, polimerik misellerin Entrapped Loaded

Amphiphilic block copolymers like polyethyleneglycol-block-polylactic acid (PEG-b-PLA) can self-assemble into micelles above their critical micellar ...

Synthesis, Characterization, and Functionalization of Hybrid Au/CdS and Au/ZnS Core/Shell Nanoparticles

Plasmonic nanoparticles are an attractive material for light harvesting applications due to their easily modified surface, high surface area and large extinction coefficients which can be tuned across the visible spectrum. Research into the plasmonic enhancement of optical transitions has become popular, due to the possibility of altering and in some cases improving photo-absorption or emission properties of nearby chromophores such as molecular dyes or quantum dots. The electric field of the plasmon can couple with the excitation dipole of a chromophore, perturbing the electronic states involved in the transition and leading to increased absorption and emission rates. These enhancements can also be negated at close distances by energy transfer mechanism, making the spatial arrangement of the two species critical. Ultimately, enhancement of light harvesting efficiency in plasmonic solar cells could lead to thinner and, therefore, lower cost devices. The development of hybrid core/shell particles could offer a solution to this issue. The addition of a dielectric spacer between a gold nanoparticles and a chromophore is the proposed method to control the exciton plasmon coupling strength and thereby balance losses with the plasmonic gains. A detailed procedure for the coating of gold nanoparticles with CdS and ZnS semiconductor shells is presented. The nanoparticles show high uniformity with size control in both the core gold particles and shell species allowing for a more accurate investigation into the plasmonic enhancement of external chromophores.

The synthesis of uniform gold nanoparticles coated with semiconductor shells of CdS or ZnS is performed. The semiconductor coating is conducted by first depositing a silver sulfide shell and exchanging the silver cations for zinc or cadmium cations.

Sentezi, Karakterizasyonu ve Hibrid Au / CdS ve Au / ZnS Çekirdek / Shell Nanopartiküller işlevselleştirilmesi

Plasmonic nanoparticles are an attractive material for light harvesting applications due to their easily modified surface, high surface area and large ...

Synthesis and Characterization of Supramolecular Colloids

Control over colloidal assembly is of utmost importance for the development of functional colloidal materials with tailored structural and mechanical properties for applications in photonics, drug delivery and coating technology. Here we present a new family of colloidal building blocks, coined supramolecular colloids, whose self-assembly is controlled through surface-functionalization with a benzene-1,3,5-tricarboxamide (BTA) derived supramolecular moiety. Such BTAs interact via directional, strong, yet reversible hydrogen-bonds with other identical BTAs. Herein, a protocol is presented that describes how to couple these BTAs to colloids and how to quantify the number of coupling sites, which determines the multivalency of the supramolecular colloids. Light scattering measurements show that the refractive index of the colloids is almost matched with that of the solvent, which strongly reduces the van der Waals forces between the colloids. Before photo-activation, the colloids remain well dispersed, as the BTAs are equipped with a photo-labile group that blocks the formation of hydrogen-bonds. Controlled deprotection with UV-light activates the short-range hydrogen-bonds between the BTAs, which triggers the colloidal self-assembly. The evolution from the dispersed state to the clustered state is monitored by confocal microscopy. These results are further quantified by image analysis with simple routines using ImageJ and Matlab. This merger of supramolecular chemistry and colloidal science offers a direct route towards light- and thermo-responsive colloidal assembly encoded in the surface-grafted monolayer.

A protocol for the synthesis and characterization of colloids coated with supramolecular moieties is described. These supramolecular colloids undergo self-assembly upon the activation of the hydrogen-bonds between the surface-anchored molecules by UV-light.

Supramoleküler Kolloidlerin Sentezi ve Karakterizasyonu

Control over colloidal assembly is of utmost importance for the development of functional colloidal materials with tailored structural and mechanical ...

Low-energy Cathodoluminescence for (Oxy)Nitride Phosphors

Nitride and oxynitride (Sialon) phosphors are good candidates for the ultraviolet and visible emission applications. High performance, good stability and flexibility of their emission properties can be achieved by controlling their composition and dopants. However, a lot of work is still required to improve their properties and to reduce the production cost. A possible approach is to correlate the luminescence properties of the Sialon particles with their local structural and chemical environment in order to optimize their growth parameters and find novel phosphors. For such a purpose, the low-voltage cathodoluminescence (CL) microscopy is a powerful technique. The use of electron as an excitation source allows detecting most of the luminescence centers, revealing their luminescence distribution spatially and in depth, directly comparing CL results with the other electron-based techniques, and investigating the stability of their luminescence properties under stress. Such advantages for phosphors characterization will be highlighted through examples of investigation on several Sialon phosphors by low-energy CL.

Low-energy Cathodoluminescence for OxyNitride Phosphors

An excellent chemical and luminescence stabilities of (oxy)nitride phosphors present it as an promising alternative to currently used sulfide and oxide phosphors. In this paper, we present the way to investigate its local luminescence properties using low-energy cathodoluminescence (CL).

(Oxy) Nitrit Fosforilazın için düşük enerji Katodolüminesans

Nitride and oxynitride (Sialon) phosphors are good candidates for the ultraviolet and visible emission applications. High performance, good stability and ...

Preparation and In Vitro Characterization of Dendrimer-based Contrast Agents for Magnetic Resonance Imaging

Paramagnetic complexes of gadolinium(III) with acyclic or macrocyclic chelates are the most commonly used contrast agents (CAs) for magnetic resonance imaging (MRI). Their purpose is to enhance the relaxation rate of water protons in tissue, thus increasing the MR image contrast and the specificity of the MRI measurements. Current clinically approved contrast agents are low molecular weight molecules that are rapidly cleared from the body. The use of dendrimers as carriers of paramagnetic chelators can play an important role in the future development of more efficient MRI contrast agents. Specifically, the increase in local concentration of the paramagnetic species results in a higher signal contrast. Furthermore, this CA provides a longer tissue retention time due to its high molecular weight and size. Here, we demonstrate a convenient procedure for the preparation of macromolecular MRI contrast agents based on poly(amidoamine) (PAMAM) dendrimers with monomacrocyclic DOTA-type chelators (DOTA &#8211; 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetate). The chelating unit was appended by exploiting the reactivity of the isothiocyanate (NCS) group towards the amine surface groups of the PAMAM dendrimer to form thiourea bridges. Dendrimeric products were purified and analyzed by means of nuclear magnetic resonance spectroscopy, mass spectrometry, and elemental analysis. Finally, high resolution MR images were recorded and the signal contrasts obtained from the prepared dendrimeric and the commercially available monomeric agents were compared.

Preparation and In Vitro Characterization of Dendrimer-based Contrast Agents for Magnetic Resonance Imaging

This protocol describes the preparation and characterization of a dendrimeric magnetic resonance imaging (MRI) contrast agent that carries cyclen-based macrocyclic chelates coordinating paramagnetic gadolinium ions. In a series of MRI experiments in vitro, this agent produced an amplified MRI signal when compared to the commercially available monomeric analogue.

Hazırlama ve<em&gt; İn Vitro</em&gt; Manyetik Rezonans Görüntüleme için Dendrimer tabanlı Kontrast Ajanlar Karakterizasyonu

Paramagnetic complexes of gadolinium(III) with acyclic or macrocyclic chelates are the most commonly used contrast agents (CAs) for magnetic resonance ...

Influence of Hybrid Perovskite Fabrication Methods on Film Formation, Electronic Structure, and Solar Cell Performance

Hybrid organic/inorganic halide perovskites have lately been a topic of great interest in the field of solar cell applications, with the potential to achieve device efficiencies exceeding other thin film device technologies. Yet, large variations in device efficiency and basic physical properties are reported. This is due to unintentional variations during film processing, which have not been sufficiently investigated so far. We therefore conducted an extensive study of the morphology and electronic structure of a large number of CH3NH3PbI3 perovskite where we show how the preparation method as well as the mixing ratio of educts methylammonium iodide and lead(II) iodide impact properties like film formation, crystal structure, density of states, energy levels, and ultimately the solar cell performance.

We present an extensive study on the effects of different fabrication methods for organic/inorganic perovskite thin films by comparing crystal structures, density of states, energy levels, and ultimately the solar cell performance.

Film Oluşumunda Hybrid Perovskit Fabrikasyon Yöntemleri, Elektronik Yapısı ve Güneş Pili Performans Etkisi

Hybrid organic/inorganic halide perovskites have lately been a topic of great interest in the field of solar cell applications, with the potential to ...