Name: monitoring the effects of illumination on the structure of conjugated polymer gels using neutron scattering
Uploaded: 2017-12-21T12:30:00.000+00:00
Duration: 6 min 16 s
Description: Watch this Scientific Journal Video about Monitoring the Effects of Illumination on the Structure of Conjugated Polymer Gels Using Neutron Scattering at JoVE.com

著者では、全米科学財団 (DMR-1409034) を感謝するこのプロジェクトのサポートのため。この作業で使用するこれらの施設をサポートする部分で全米科学財団によって契約の下で USANS 施設で商業、技術、米国商務省国立標準研究所のサポートを認めなければ違います。DMR-0944772。この研究の SAN の実験は、オークリッジ国立研究所の高流束同位体の原子炉で、科学的なユーザー設備部門、基本的なエネルギー科学のオフィス、米国エネルギー省によって後援された完了しました。

化学物質のすべての処理は、適切な個人用保護具と安全フード内で実施する必要があります。電離放射線にさらされる、すべてのサンプルは、施設放射性管理技術者の監督の下処理必要があります。このプロトコルは、適切な放射線安全教育を終了した個人によって行われました。
1. d ODCB ソリューションで P3HT の準備
<ol>
	<li>サンプルの収集
	<ol>
		<li>高ポリアルキルチオフェンの 1 g を購入 (&#62; 90%)P3HT 分子量範囲 15-40 k.</li>
		<li>高純度の 5 g を購入 (&#62; 90 原子 % 重水素) d-4 1, 2 ODCB。</li>
	</ol>
	</li>
	<li>サンプル準備
	<ol>
		<li>ガラスの瓶に 0.45 μ m ふるいをすべて d ODCB ソリューションをフィルターします。</li>
		<li>並んでホイル キャップと 5 g のバイアルで d ODCB の 1.66 g P3HT の 0.34 g を組み合わせます。 注: サンプルの作成および転送プロセス全体を通してすべての回でサンプルが公開されます周囲光の強度を最小限に抑えます。</li>
		<li>電磁攪拌棒を加えるバイアル、キャップを保護パラフィルムでシールします。</li>
		<li>完全ソリューションへ光の露出を防ぐためにアルミ箔にバイアルをラップします。</li>
		<li>有効な磁気攪拌棒 1-3 h の 70 ° C のホット プレートにサンプルを配置します。</li>
		<li>熱と攪拌ソリューションが完全に同質な (できれば完全な分散を確保するためサンプル加熱・攪拌しながら一晩を残して) から削除します。</li>
		<li>正しく洗浄バイアルからソリューションに転送 (アセトンと水の洗口液別) とガラス ピペットを使用して 1 または 2 の mm 厚い水晶バンジョー セル。 注: は、転送は大幅にこのプロセスを簡素化する直前に 70 ° C に加熱オーブン ガラス ピペットを加熱します。</li>
		<li>バンジョー セルのキャップを貼付し、パラフィルムでシールします。</li>
		<li>完全な暗闇の場所バンジョー セル (密封された箱の内側やアルミ箔に包まれた)。</li>
		<li>同様の方法で d ODCB (満員) と散乱実験のためのそれぞれ、溶媒の背景と空のセルとして機能する、空のバンジョー セルのみが含まれているサンプルを組み立てます。</li>
	</ol>
	</li>
</ol>
2. 中性子散乱実験
<ol>
	<li>「暗い」の環境で SAN を実験します。
	<ol>
		<li>楽器の科学者からの援助、70-20 ° c. の温度のランプを指示できる必要な温度コントロール サンプル ステージが付されていることを確認します。</li>
		<li>適切に大きさで分類された保有物ブロック、セキュリティで保護された、およびラベルにバンジョー セルを配置します。</li>
		<li>周囲の光が試料に入射しないように 0.1 mm 厚のアルミ箔とブロック全体をラップします。サンプル段階で包まれたブロックの適切なフィットを確保するため箔の変形を最小限に抑えます。サンプル ステージ内でこのラップ ブロックとサンプルを配置します。</li>
		<li>楽器の科学者からの支援を受けて、適切な楽器配置と適切な標準による校正を完了します。最終的に約 0.001 0.1 a 完全な Q 範囲を許可する低い Q 領域 (~0.001 Å-1) へのアクセスを確保するため (18 の m) でのインスタンスの設定最大に近い検出器距離 Å-1。これは 500 〜 最大のスケール長さの調査により、nm。</li>
		<li>楽器の科学者の助けを借りて、P3HT と溶媒サンプル カウント率を収集し、確保約 500,000 に 1,000,000 のサンプルごとの総検出器数を達成するために必要な散乱時間数を決定するための計算を実行良質の統計データ。</li>
		<li>この情報により、70-20 ° C の温度ランプとデータ収集のプロセスを指示するサンプル スクリプトを作成します。離散温度範囲ポイント ベスト ・ カバーに与えられた時間制約内全体の範囲例えばすべての 2 ° c. を選択します。ランプのすべてのポイントの 3 の独立したエントリは、スクリプトの: 所望の温度、散乱を収集すると、前に熱平衡にシステムを許可する待機期間 (~ 15 分) と散乱測定実施自体への変更、必要な検出器を達成するために適切な時間をカウントします。</li>
		<li>楽器とスクリプトが準備されると、スクリプトを実行し、テストを開始します。必ず温度ランプ) を除いた溶媒と空セル同様のデータを収集してください。また、各サンプルのブロックされたビーム計測伝送データを収集します。</li>
	</ol>
	</li>
	<li>「光」の環境で SAN を実験します。
	<ol>
		<li>「暗い」の実験の完了次第、段階からサンプルを移動セキュリティで保護されたまたは卓上配置し、放射線安全プロトコルを見ながらすべてのアルミ箔を削除します。</li>
		<li>リードは効果的に散乱コレクションの位置に関連付けられている段階でサンプル スロットを照らすようにサンプル ステージ近くハロゲン光源を備えた光照明器具を配置します。</li>
		<li>校正光メーター、記録光の強度はサンプルが座っている位置に最大輝度で照明が提供を使用してください。強度値は、照明およびサンプルのステージ構成によって異なります、しかし、少なくとも 5,000 ルクスの照度が必要があります。</li>
		<li>この照明のセットアップは正しく組み立ては、一度サンプルをステージに戻り、照明はアクティブなサンプルを照明して正しくことを確認、再び 70 ° C に加熱、適切な平衡を許可する、暗闇の中で実行されるデータ コレクションの手順を繰り返しますこの手順の全体の期間中断のない徹底した直接露光を提供する光の照明のサンプル。</li>
	</ol>
	</li>
	<li>USANS 実験
	<ol>
		<li>バンジョーの石英セルを使用して同様の方法で USANS サンプルを準備し、温度制御サンプル ステージ内で銅やチタン ブロックに配置します。</li>
		<li>楽器の科学者の助けを借りて、合わせ、約 10-5 - 10-3 Å-1長さを許可の Q 値の解析を許可する特定の中性子波長でバッファーの必要な数を用いる計測器の校正プローブにミクロン スケールします。</li>
		<li>熱平衡と以前学んだ各温度下でのデータ収集を可能にする SAN 実験と同様の実験のスクリプトを開発します。</li>
		<li>SAN の実験を再度複製、実行スクリプト「暗い」の条件の下で一度、もう一度条件"「光」。</li>
	</ol>
	</li>
</ol>
3。データ削減と解析
<ol>
	<li>SANS の削減と解析
	<ol>
		<li>それぞれ削減プログラムを使用して、32入力散乱、背景 (溶剤)、空のセル、ブロックされたビームおよび適切な背景差分と絶対に散乱データの変換を達成するために透過率測定のデータ ファイルcm-1に強度の単位。</li>
		<li>適切に縮小データ、実験的散乱データを 2 つの継ぎ手方程式を楕円柱モデル33を通じて nanofibril 集計を表す 1 つの線形加算であるモデルのあてはめによる分析を開始し、ポリマー溶液の自由な鎖を考慮して別には、ボリューム モデルが除外されます。34,35以下の方程式では、このアプローチの組み合わせモデルについて説明します。 
		<img alt="Equation 1" src="/files/ftp_upload/56163/56163eq1.jpg"> この式、φ のP3HT P3HT のソリューションでは、合計の体積を説明します<img alt="Equation 2" src="/files/ftp_upload/56163/56163eq2.jpg">現在集計 P3HT の体積は、楕円シリンダー、 PPEVとしてモデル化除外フリー チェーン ボリュームPECM P3HT のフォーム ファクター記述集計、楕円柱フォーム ファクターと<img alt="Equation 3" src="/files/ftp_upload/56163/56163eq3.jpg">と<img alt="Equation 4" src="/files/ftp_upload/56163/56163eq4.jpg">散乱長密度 (SLD) コントラスト P3HT 集計および溶媒と無料の間は、P3HT チェーンや溶剤、それぞれ。自分の化学の知識を持つシステムのすべてのコンポーネントの SLD 値が計算される組成と質量密度と、SLD 電卓としての使用そのほとんど中性子解析プログラムのまたはオンライン。36</li>
		<li>適切なフィッティング手順に NCNR イゴール マクロ37または SASView フィッティング プログラムを使用して光と闇の定量化を可能にすべて温ゲル化システムのキー構造パラメーターの値を取得、温度と光の露出の機能としてこのプロセスの中で発生する形態の進化。これらの構造のパラメーター、nanofibrils の断面領域が含まれて、無料チェーン半径旋回 (Rg) と前処理指数、物質的な nanofibril の段階で現在の総量の定性的な評価。</li>
	</ol>
	</li>
	<li>USANS 削減と解析
	<ol>
		<li>それぞれ削減プログラムを使用すると、散乱データや cm-1の絶対強度単位の単一の減少曲線にデータをマージする各バッファーの背景データを入力します。</li>
		<li>USANS の長さスケールででき集計 Rg値の取得、集計散乱パターンの定量的評価を可能にする Guinier 前処理力法律モデルを使用してデータを分析します。38フィット NCNR イゴール マクロ37または SASView フィッティング プログラムを通じてこのメソッドを使用して、すべての温度と照明条件間でマクロ団粒 Rgの比較を許可します。</li>
	</ol>
	</li>
</ol>

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C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mesoscale+Morphology+and+Charge+Transport+in+Colloidal+Networks+of+Poly(3-Hexylthiophene).">Mesoscale Morphology and Charge Transport in Colloidal Networks of Poly(3-Hexylthiophene).</a> Macromolecules. 44, 3801-3809 (2011).</li><li>Tretiak, S., Saxena, A., Martin, R., Bishop, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Conformational+Dynamics+of+Photoexcited+Conjugated+Molecules.">Conformational Dynamics of Photoexcited Conjugated Molecules.</a> Phys. Rev. Lett. 89 (9), 97402 (2002).</li><li>Botiz, I., Freyberg, P., Stingelin, N., Yang, A. C. -. M., Reiter, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Reversibly+Slowing+Dewetting+of+Conjugated+Polymers+by+Light.">Reversibly Slowing Dewetting of Conjugated Polymers by Light.</a> Macromolecules. 46, 2352-2356 (2013).</li><li>Botiz, 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=Enhancing+the+Photoluminescence+Emission+of+Conjugated+MEH-PPV+by+Light+Processing.">Enhancing the Photoluminescence Emission of Conjugated MEH-PPV by Light Processing.</a> ACS Appl. Mater. Interfaces. 6 (7), 4974-4979 (2014).</li><li>Morgan, B., Dadmun, 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=Illumination+Alters+the+Structure+of+Gels+Formed+from+the+Optoelectronic+Material+P3HT.">Illumination Alters the Structure of Gels Formed from the Optoelectronic Material P3HT.</a> Polymer. 108, 313-321 (2017).</li><li>Morgan, B., Dadmun, 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=Illumination+of+Conjugated+Polymer+in+Solution+Alters+Its+Conformation+and+Thermodynamics.">Illumination of Conjugated Polymer in Solution Alters Its Conformation and Thermodynamics.</a> Macromolecules. 49 (9), 3490-3496 (2016).</li><li>Ilavsk, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Phase+Transition+in+Swollen+Gels.+2.+Effect+of+Charge+Concentration+on+the+Collapse+and+Mechanical+Behavior+of+Polyacrylamide+Networks.">Phase Transition in Swollen Gels. 2. Effect of Charge Concentration on the Collapse and Mechanical Behavior of Polyacrylamide Networks.</a> Macromolecules. 15, 782-788 (1982).</li><li>Tanaka, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Collapse+of+Gels+and+the+Critical+Endpoint.">Collapse of Gels and the Critical Endpoint.</a> Phys. Rev. Lett. 40 (12), 820-823 (1978).</li><li>. SANS &amp; USANS Data Reduction and Analysis Available from: <a target="_blank" href="https://www.ncnr.nist.gov/programs/sans/data/red_anal.html">https://www.ncnr.nist.gov/programs/sans/data/red_anal.html</a> (2017)</li><li>Feigin, L., Svergun, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Structure Analysis by Small-Angle X-Ray and Neutron Scattering. , (1987).</li><li>Mittelbach, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Zur+Rontgenkleinwinkelstreuung+verdunnter+kolloider+systeme.">Zur Rontgenkleinwinkelstreuung verdunnter kolloider systeme.</a> Acta Phys. Austriaca. 14, 185-211 (1961).</li><li>Schulz, G. Z. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=&#220;ber+die+Kinetik+der+Kettenpolymerisationen.">&#220;ber die Kinetik der Kettenpolymerisationen.</a> Z. Phys. Chem. 43, 25 (1935).</li><li>. Neutron activation and scattering calculator Available from: <a target="_blank" href="https://www.ncnr.nist.gov/resources/activation">https://www.ncnr.nist.gov/resources/activation</a> (2017)</li><li>Kline, S. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Reduction+and+Analysis+of+SANS+and+USANS+Data+Using+IGOR+Pro.">Reduction and Analysis of SANS and USANS Data Using IGOR Pro.</a> J. Appl. Crystallogr. 39 (6), 895-900 (2006).</li><li>Guinier, A., Fournet, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Small-Angle Scattering of X-Rays. , (1955).</li></ol>

著者が明らかに何もありません。

まず、温度の関数として SAN データを見ると、楕円シリンダー モデル尺度の増加 P3HT ゲル化反応の進行にどの一致処理 nanofibril 相に存在量の著しい増加を示します.同時に、フリー チェーン Rgの減少は悪化の熱力学条件温度に関連付けられて減少指数を明らかには今も P3HT チェーンでチェーン崩壊を引き起こしている前処理の増加と共にソリューションです。マークを示す USANS デー?...

共役ポリマーは、有機発光ダイオード、有機半導体、化学センサー、有機薄膜太陽電池などのデバイスの広い範囲で活用できる材料をお約束します。1,2,3,4,5,6これらのデバイスのパフォーマンスの重要な側面は順序および共役高分子活性層の固体状態での梱包です。7,8,9,10,11,12,13,14この形態は主によってあらかじめ決定ソリューションだけでなく、これらのソリューションが基板にキャストし、溶媒を除去として進化構造高分子鎖のコンフォメーションの両方。適当な溶剤でモデル光ポリマーの典型的なゾル-ゲル転移全体に存在の構造を研究することによってこれらのシステム効果的にモデル化できると定量的垣間見る、自己組織化材料蒸着中に発生得られます。15,16,17,18,19,20
具体的には、検討、溶媒重水素オルト-ジクロロ ベンゼン (ODCB)、さまざまな有機電子デバイス作製のための適合性のための広範な使用を見ている高分子-溶媒系の共役高分子ベンチマーク P3HTテクニック。23,24,25この特定の溶媒環境では P3HT チェーンなど適切な環境刺激の時に集計を開始温度や溶媒の品質の損失。このアセンブリ プロセスは主要な提案された経路の 1 つで、調査中のため本人漸進的なプロセスであると考えられている正確なメカニズム P3HT 分子 π-スタック nanofibrils、その後、彼ら自身と呼ばれる層状のナノ集合体を形成するには凝集大きいミクロン スケール マクロ会合体を形成します。24これらの経路と結果の構造形成を理解することは正しく予測し、最適なデバイスのアクティブなレイヤーの形態形成に影響を与えるキーです。
正確にこれらのアクティブなレイヤー アーキテクチャの形成を監督の究極の目標に向かって非破壊的共役ポリマー形態の in-situ を変更する追加実験と産業方式を開発する必要性が存在します。1 つの比較的新しい方法論を中心に安価な手段としてその可能性に向かって指して計算と実験の結果と高分子鎖の形態を変更するための露光の使用。25,26,27最近の私たちの研究室での作業は照明にポリマー チェーン サイズの顕著な変更につながる、希薄溶液における共役高分子-溶媒相互作用の光誘起変化の存在を示しています。30,31 、ここで提案するサーモスタット制御によって指示されるゲル化過程を通して直接光に多く集中している共役高分子溶液を公開することの影響を効果的に監視することによってこの仕事を継続するためのプロトコル温度ランプ。中性子散乱を用いてミクロン、他のより一般的なレオロジーや分光学的楽器を通じて不可能能力をオングストロームから長さスケールで高分子-溶媒ゾル-ゲル系の構造パラメーターのロバスト解析できるのでメソッド。16,17,30,31 、正しく分析小・極小角を比較することにより中性子とゲルのアセンブリのデータ形成される照明駆動によってもたらされる構造的な違い完全な暗闇の中で収集された同一のデータへの照明の下で効果を包括的に識別して定量化することができます。

<table><tbody><tr><td>M(106) poly(3-hexylthiophene-2,5-diyl) (P3HT)</td><td>Ossila</td><td>104934-50-1</td><td>Conjugated polymer</td></tr><tr><td>deuterated 1,2 ortho-dichlorobenzene (ODCB)</td><td>Sigma Aldrich</td><td>AC321260050</td><td>solvent</td></tr></tbody></table>

monitoring the effects of illumination on the structure of conjugated polymer gels using neutron scattering

Π 共役系高分子の存在の両方の高濃度溶液と白い光の不在のゲル化過程を効果的に監視するためのプロトコルを示す.制御温度の傾斜路を設けることによってこれらの材料のゲル化正確に監視できる効果的に有機のソリューション蒸着フェーズ中に発生した条件を模したこの構造の進化を進める彼らされました。電子デバイス作製。中性子小角散乱 (SAN) と適切なフィッティング プロトコルと共に超小角中性子散乱 (USANS) を使用してこのプロセスを通して選択構造パラメーターの進化を定量化します。徹底的な分析は、ゲル化過程の中で継続的な露光が最終的に形成されたゲルの構造を大幅変更されることを示します。具体的には、poly(3-hexylthiophene-2,5-diyl) (P3HT) ナノ集合体の凝集過程が最終的に共役ポリマー微細構造の成長の遅滞の結果、照明の存在によって低下し、小さいスケールのマクロ集計クラスターの形成。

を介して SAN と USANS 実験、d ODCB P3HT のゲル化過程は 20 ° C で完全にゲル化状態に 70 ° C で分散したソリューション状態から監視が効果的これらの実験は、両方の完全な暗闇の中で、白色光の照明の下で行った。図 1には、これらの実験から近似例曲線を図 2に示すようにいくつかの例を削減 SAN データ曲線が表示されます。?...

Watch this Scientific Journal Video about Monitoring the Effects of Illumination on the Structure of Conjugated Polymer Gels Using Neutron Scattering at JoVE.com

Monitoring the Effects of Illumination on the Structure of Conjugated Polymer Gels Using Neutron Scattering

光から形成されたゲルの分析のためのプロトコル共役高分子 poly(3-hexylthiophene-2,5-diyl) (P3HT) 小さなを使用して、プレゼンスと照明の有無の両方で超小角中性子散乱が提示されます。

中性子散乱法を用いた共役高分子ゲルの構造に対する光照射効果のモニタリング

We demonstrate a protocol to effectively monitor the gelation process of a high concentration solution of conjugated polymer both in the presence and ...

monitoring-effects-illumination-on-structure-conjugated-polymer-gels

Research

JoVE Journal

Chemistry

5.7K ビュー.  University of Tennessee, Knoxville. 光から形成されたゲルの分析のためのプロトコル共役高分子 poly(3-hexylthiophene-2,5-diyl) (P3HT) 小さなを使用して、プレゼンスと照明の有無の両方で超小角中性子散乱が提示されます。

ビデオ: Monitoring the Effects of Illumination on the Structure of Conjugated Polymer Gels Using Neutron Scattering

Using Neutron Spin Echo Resolved Grazing Incidence Scattering to Investigate Organic Solar Cell Materials

The spin echo resolved grazing incidence scattering (SERGIS) technique has been used to probe the length-scales associated with irregularly shaped crystallites. Neutrons are passed through two well defined regions of magnetic field; one before and one after the sample. The two magnetic field regions have opposite polarity and are tuned such that neutrons travelling through both regions, without being perturbed, will undergo the same number of precessions in opposing directions. In this case the neutron precession in the second arm is said to &#34;echo&#34; the first, and the original polarization of the beam is preserved. If the neutron interacts with a sample and scatters elastically the path through the second arm is not the same as the first and the original polarization is not recovered. Depolarization of the neutron beam is a highly sensitive probe at very small angles (&#60;50&#160;&#956;rad) but still allows a high intensity, divergent beam to be used. The decrease in polarization of the beam reflected from the sample as compared to that from the reference sample can be directly related to structure within the sample.
In comparison to scattering observed in neutron reflection measurements the SERGIS signals are often weak and are unlikely to be observed if the in-plane structures within the sample under investigation are dilute, disordered, small in size and polydisperse or the neutron scattering contrast is low. Therefore, good results will most likely be obtained using the SERGIS technique if the sample being measured consist of thin films on a flat substrate and contain scattering features that contains a high density of moderately sized features (30 nm to 5 &#181;m) which scatter neutrons strongly or the features are arranged on a lattice. An advantage of the SERGIS technique is that it can probe structures in the plane of the sample.

Progress has been made in utilizing spin echo resolved grazing incidence scattering (SERGIS) as a neutron scattering technique to probe the length-scales in irregular samples. Crystallites of [6,6]-phenyl-C61-butyric acid methyl ester have been probed using the SERGIS technique and the results confirmed by optical and atomic force microscopy.

中性子スピンエコーを使用して放牧発生率散乱を解決し、有機太陽電池材料を調査する

The spin echo resolved grazing incidence scattering (SERGIS) technique has been used to probe the length-scales associated with irregularly shaped ...

工学

Measurement of Scattering Nonlinearities from a Single Plasmonic Nanoparticle

Plasmonics, which are based on the collective oscillation of electrons due to light excitation, involve strongly enhanced local electric fields and thus have potential applications in nonlinear optics, which requires extraordinary optical intensity. One of the most studied nonlinearities in plasmonics is nonlinear absorption, including saturation and reverse saturation behaviors. Although scattering and absorption in nanoparticles are closely correlated by the Mie theory, there has been no report of nonlinearities in plasmonic scattering until very recently. 
Last year, not only saturation, but also reverse saturation of scattering in an isolated plasmonic particle was demonstrated for the first time. The results showed that saturable scattering exhibits clear wavelength dependence, which seems to be directly linked to the localized surface plasmon resonance (LSPR). Combined with the intensity-dependent measurements, the results suggest the possibility of a common mechanism underlying the nonlinear behaviors of scattering and absorption. These nonlinearities of scattering from a single gold nanosphere (GNS) are widely applicable, including in super-resolution microscopy and optical switches. 
In this paper, it is described in detail how to measure nonlinearity of scattering in a single GNP and how to employ the super-resolution technique to enhance the optical imaging resolution based on saturable scattering. This discovery features the first super-resolution microscopy based on nonlinear scattering, which is a novel non-bleaching contrast method that can achieve a resolution as low as l/8 and will potentially be useful in biomedicine and material studies.

Saturable and reverse saturable scattering were discovered in isolated plasmonic particles and adopted as a novel non-bleaching contrast method in super-resolution microscopy. Here the experimental procedures of detecting and extracting nonlinear scattering are explained in detail, as well as how to enhance resolution with the aid of saturated excitation microscopy.

シングルプラズモニックナノ粒子からの散乱非線形性の測定

Plasmonics, which are based on the collective oscillation of electrons due to light excitation, involve strongly enhanced local electric fields and thus ...

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.

超分子コロイドの合成とキャラクタリゼーション

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

化学

Controlled Synthesis and Fluorescence Tracking of Highly Uniform Poly(N-isopropylacrylamide) Microgels

Stimuli-sensitive poly(N-isopropylacrylamide) (PNIPAM) microgels have various prospective practical applications and uses in fundamental research. In this work, we use single particle tracking of fluorescently labeled PNIPAM microgels as a showcase for tuning microgel size by a rapid non-stirred precipitation polymerization procedure. This approach is well suited for prototyping new reaction compositions and conditions or for applications that do not require large amounts of product. Microgel synthesis, particle size and structure determination by dynamic and static light scattering are detailed in the protocol. It is shown that the addition of functional comonomers can have a large influence on the particle nucleation and structure. Single particle tracking by wide-field fluorescence microscopy allows for an investigation of the diffusion of labeled tracer microgels in a concentrated matrix of non-labeled microgels, a system not easily investigated by other methods such as dynamic light scattering.

Controlled Synthesis and Fluorescence Tracking of Highly Uniform PolyN-isopropylacrylamide Microgels

Non-stirred precipitation polymerization provides a rapid, reproducible prototyping approach to the synthesis of stimuli-sensitive poly(N-isopropylacrylamide) microgels of narrow size distribution. In this protocol synthesis, light scattering characterization and single particle fluorescence tracking of these microgels in a wide-field microscopy setup are demonstrated.

制御された合成および均一性の高いポリの蛍光トラッキング（<em&gt; N</em&gt; -isopropylacrylamide）ミクロゲル

Stimuli-sensitive poly(N-isopropylacrylamide) (PNIPAM) microgels have various prospective practical applications and uses in fundamental research. In this ...

Advanced Compositional Analysis of Nanoparticle-polymer Composites Using Direct Fluorescence Imaging

The fabrication of polymer-nanoparticle composites is extremely important in the development of many functional materials. Identifying the precise composition of these materials is essential, especially in the design of surface catalysts, where the surface concentration of the active component determines the activity of the material. Antimicrobial materials which utilize nanoparticles are a particular focus of this technology. Recently swell encapsulation has emerged as a technique for inserting antimicrobial nanoparticles into a host polymer matrix. Swell encapsulation provides the advantage of localizing the incorporation to the external surfaces of materials, which act as the active sites of these materials. However, quantification of this nanoparticle uptake is challenging. Previous studies explore the link between antimicrobial activity and surface concentration of the active component, but this is not directly visualized. Here we show a reliable method to monitor the incorporation of nanoparticles into a polymer host matrix via swell encapsulation. We show that the surface concentration of CdSe/ZnS nanoparticles can be accurately visualized through cross-sectional fluorescence imaging. Using this method, we can quantify the uptake of nanoparticles via swell encapsulation and measure the surface concentration of encapsulated particles, which is key in optimizing the activity of functional materials.

Here we present a reliable method to monitor the incorporation of nanoparticles into a polymer host matrix via swell encapsulation. We show that the surface concentration of cadmium selenide quantum dots can be accurately visualized through cross-sectional fluorescence imaging.

直接蛍光イメージングを用いたナノ粒子 - ポリマー複合材料の高度な組成分析

The fabrication of polymer-nanoparticle composites is extremely important in the development of many functional materials. Identifying the precise ...

Measurement of Particle Size Distribution in Turbid Solutions by Dynamic Light Scattering Microscopy

A protocol for measuring polydispersity of concentrated polymer solutions using dynamic light scattering is described. Dynamic light scattering is a technique used to measure the size distribution of polymer solutions or colloidal particles. Although this technique is widely used for the assessment of polymer solutions, it is difficult to measure the particle size in concentrated solutions due to the multiple scattering effect or strong light absorption. Therefore, the concentrated solutions should be diluted before measurement. Implementation of the confocal optical component in a dynamic light scattering microscope1 helps to overcome this barrier. Using such a microscopic system, both transparent and turbid systems can be analyzed under the same experimental setup without a dilution. As a representative example, a size distribution measurement of a temperature-responsive polymer solution was performed. The sizes of the polymer chains in an aqueous solution were several tens of nanometers at a temperature below the lower critical solution temperature (LCST). In contrast, the sizes increased to more than 1.0 &#181;m when above the LCST. This result is consistent with the observation that the solution turned turbid above the LCST.

A protocol for the direct measurement of particle size distribution in concentrated solutions using dynamic light scattering microscopy is presented.

動的光散乱顕微鏡による濁りソリューションにおける粒度分布の測定

A protocol for measuring polydispersity of concentrated polymer solutions using dynamic light scattering is described. Dynamic light scattering is a ...

Novel Techniques for Observing Structural Dynamics of Photoresponsive Liquid Crystals

We discuss in this article the experimental measurements of the molecules in liquid crystal (LC) phase using the time-resolved infrared (IR) vibrational spectroscopy and time-resolved electron diffraction. Liquid crystal phase is an important state of matter that exists between the solid and liquid phases and it is common in natural systems as well as in organic electronics. Liquid crystals are orientationally ordered but loosely packed, and therefore, the internal conformations and alignments of the molecular components of LCs can be modified by external stimuli. Although advanced time-resolved diffraction techniques have revealed picosecond-scale molecular dynamics of single crystals and polycrystals, direct observations of packing structures and ultrafast dynamics of soft materials have been hampered by blurry diffraction patterns. Here, we report time-resolved IR vibrational spectroscopy and electron diffractometry to acquire ultrafast snapshots of a columnar LC material bearing a photoactive core moiety. Differential-detection analyses of the combination of time-resolved IR vibrational spectroscopy and electron diffraction are powerful tools for characterizing structures and photoinduced dynamics of soft materials.

Here, we present the protocols of differential-detection analyses of time-resolved infrared vibrational spectroscopy and electron diffraction which enable observations of the deformations of local structures around photoexcited molecules in a columnar liquid crystal, giving an atomic perspective on the relationship between the structure and the dynamics of this photoactive material.

光応答性液晶の構造ダイナミクスを観察する手法

We discuss in this article the experimental measurements of the molecules in liquid crystal (LC) phase using the time-resolved infrared (IR) vibrational ...

Photogeneration of N-Heterocyclic Carbenes: Application in Photoinduced Ring-Opening Metathesis Polymerization

We report a method to generate the N-heterocyclic carbene (NHC) 1,3-dimesitylimidazol-2-ylidene (IMes) under UV-irradiation at 365 nm to characterize IMes and determine the corresponding photochemical mechanism. Then, we describe a protocol to perform ring-opening metathesis polymerization (ROMP) in solution and in miniemulsion using this NHC-photogenerating system. To photogenerate IMes, a system comprising 2-isopropylthioxanthone (ITX) as the sensitizer and 1,3-dimesitylimidazolium tetraphenylborate (IMesH+BPh4-) as the protected form of NHC is employed. IMesH+BPh4- can be obtained in a single step by anion exchange between 1,3-dimesitylimidazolium chloride and sodium tetraphenylborate. A real-time steady-state photolysis setup is described, which hints that the photochemical reaction proceeds in two consecutive steps: 1) ITX triplet is photo-reduced by the borate anion and 2) subsequent proton transfer takes place from the imidazolium cation to produce the expected NHC IMes. Two separate characterization protocols are implemented. Firstly, CS2 is added to the reaction media to evidence the photogeneration of NHC through formation of the IMes-CS2 adduct. Secondly, the amount of NHC released in situ is quantified using acid-base titration. The use of this NHC photo-generating system for the ROMP of norbornene is also discussed. In solution, a photopolymerization experiment is conducted by mixing ITX, IMesH+BPh4-, [RuCl2(p-cymene)]2 and norbornene in CH2Cl2, then irradiating the solution in a UV reactor. In a dispersed medium, a monomer miniemulsion is first formed then irradiated inside an annular reactor to produce a stable poly(norbornene) latex.

We describe a protocol to photogenerate N-heterocyclic carbenes (NHCs) by UV irradiation of a 2-isopropylthioxanthone/imidazolium tetraphenylborate salt system. Methods to characterize the photoreleased NHC and elucidate the photochemical mechanism are proposed. The protocols for ring-opening metathesis photopolymerization in solution and miniemulsion illustrate the potential of this 2-component NHC photogenerating system.

N-複素環カルベンの生成: 光誘起開環メタセシス重合のアプリケーション

We report a method to generate the N-heterocyclic carbene (NHC) 1,3-dimesitylimidazol-2-ylidene (IMes) under UV-irradiation at 365 nm to characterize IMes ...

Light-mediated Formation and Patterning of Hydrogels for Cell Culture Applications

Click chemistries have been investigated for use in numerous biomaterials applications, including drug delivery, tissue engineering, and cell culture. In particular, light-mediated click reactions, such as photoinitiated thiol&#8722;ene and thiol&#8722;yne reactions, afford spatiotemporal control over material properties and allow the design of systems with a high degree of user-directed property control. Fabrication and modification of hydrogel-based biomaterials using the precision afforded by light and the versatility offered by these thiol&#8722;X photoclick chemistries are of growing interest, particularly for the culture of cells within well-defined, biomimetic microenvironments. Here, we describe methods for the photoencapsulation of cells and subsequent photopatterning of biochemical cues within hydrogel matrices using versatile and modular building blocks polymerized by a thiol&#8722;ene photoclick reaction. Specifically, an approach is presented for constructing hydrogels from allyloxycarbonyl (Alloc)-functionalized peptide crosslinks and pendant peptide moieties and thiol-functionalized poly(ethylene glycol) (PEG) that rapidly polymerize in the presence of lithium acylphosphinate photoinitiator and cytocompatible doses of long wavelength ultraviolet (UV) light. Facile techniques to visualize photopatterning and quantify the concentration of peptides added are described. Additionally, methods are established for encapsulating cells, specifically human mesenchymal stem cells, and determining their viability and activity. While the formation and initial patterning of thiol-alloc hydrogels are shown here, these techniques broadly may be applied to a number of other light and radical-initiated material systems (e.g., thiol-norbornene, thiol-acrylate) to generate patterned substrates.

We describe a sequential process for light-mediated formation and subsequent biochemical patterning of synthetic hydrogel matrices for three-dimensional cell culture applications. The construction and modification of hydrogels with cytocompatible photoclick chemistry is demonstrated. Additionally, facile techniques to quantify and observe patterns and determine cell viability within these hydrogels are presented.

細胞培養アプリケーションのためのヒドロゲルの光媒介形成とパターニング

Click chemistries have been investigated for use in numerous biomaterials applications, including drug delivery, tissue engineering, and cell culture. In ...

生物工学

Neutron Crystallography Data Collection and Processing for Modelling Hydrogen Atoms in Protein Structures

Neutron crystallography is a structural technique that allows determination of hydrogen atom positions within biological macromolecules, yielding mechanistically important information about protonation and hydration states while not inducing radiation damage. X-ray diffraction, in contrast, provides only limited information on the position of light atoms and the X-ray beam&#160;rapidly induces radiation damage of photosensitive&#160;cofactors and metal centers. Presented here is the workflow employed for the IMAGINE and MaNDi beamlines at Oak Ridge National Laboratory (ORNL) to obtain a neutron diffraction structure once a protein crystal of suitable size (&#62; 0.1 mm3) has been grown. We demonstrate mounting of hydrogenated protein&#160;crystals in quartz capillaries for neutron diffraction data collection. Also presented is the vapor exchange process of the mounted crystals with D2O-containing buffer to ensure replacement of hydrogen atoms at exchangeable sites with deuterium. The incorporation of deuterium reduces the background arising from the incoherent scattering of hydrogen atoms and prevents density cancellation caused by their negative coherent scattering length. Sample alignment and room temperature data collection strategies are illustrated using quasi-Laue data collection at IMAGINE at the High Flux Isotope Reactor (HFIR). Furthermore, crystal mounting and rapid freezing in liquid nitrogen for cryo-data collection to trap labile reaction intermediates is demonstrated at the MaNDi time-of-flight instrument at the Spallation Neutron Source (SNS). Preparation of the model coordinate and diffraction data files and visualization of the neutron scattering length density (SLD) maps will also be addressed. Structure refinement against neutron data-only or against joint X-ray/neutron data to obtain an all-atom structure of the protein of interest will finally be discussed. The process of determining a neutron structure will be demonstrated using crystals of the lytic polysaccharide monooxygenase Neurospora crassa LPMO9D, a copper-containing metalloprotein involved in the degradation of recalcitrant polysaccharides via oxidative cleavage of the glycosidic bond.

Neutron protein crystallography is a structural technique that permits the localization of hydrogen atoms, thereby providing important mechanistic details of protein function. We present here the workflow for mounting a protein crystal, neutron diffraction data collection, structure refinement and analysis of the neutron scattering length density maps.

中性子散乱法を用いた共役高分子ゲルの構造に対する光照射効果のモニタリング

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