固体表面との有機シリコン水化物の反応:表面触媒による自己組み立ての例
Roy Helmy1, Robert W Wenslow, Alexander Y Fadeev
1Department of Chemistry and Biochemistry, Seton Hall University, South Orange, New Jersey 07079, USA.
Journal of the American Chemical Society
|June 17, 2004
まとめ
オクタデシルシランは,催化水解によって金属酸化物上に密度が高く,水平に交結した単層を形成する. 表面の酸性と塩基性は反応性を決定し,制御された条件で最適な接ぎ木が達成されます.
科学分野:
- 表面化学について
- マテリアルサイエンス 材料科学
- ナノテクノロジー ナノテクノロジー
背景:
- オクタデシルシラン (C18H37SiH3) は,表面改変のための多用途な前駆体です.
- 自己組み立てモノレイヤ (SAM) は,材料の特性を調整するために不可欠です.
- シランの金属酸化物との反応機構を理解することは,制御された表面機能化のための鍵です.
研究 の 目的:
- オクタデシルシランの溶液相反応を,様々な高表面積の金属酸化物と研究する.
- 結果として生じるサポートモノレイヤの構造と特性を特徴付ける.
- 反応機構における金属酸化物表面特性の役割を解明する.
主な方法:
- オクタデシルシランと10種類の金属酸化物との溶液相反応.
- 化学的特徴付けのためのフーリエ変換赤外線 (FTIR) スペクトロスコピー.
- (29) 構造分析のためのSi核磁共振 (NMR) スペクトロスコーピー.
- 水素の進化を定量化するためのガス染色学.
主要な成果:
- オクタデシルシラン単層の高接合密度 (4.5-5グループ/nm2) は,ほとんどの金属酸化物で達成されています.
- Si-O-SiとSi-OH.HO-Si結合で水平に交結したSAMを形成し,酸化物への垂直結合を最小限にします.
- オクタデシルシランの完全な水解により,移植されたシランの1モルあたり約3モルH2を生成します.
- 反応速度は,金属酸化物のルイスとブロンステッド酸/塩基部位に吸収された水によって触媒化されます.
結論:
- オクタデシルシランの水解は速度を制限するステップであり,表面酸度/塩基度によって触媒化されます.
- 弱い酸性/塩基性 (シリカ,炭素,ポリマー) の材料は反応しない.
- 反応温度と,酸/塩基による表面ドーピングは,反応性を著しく高めます.
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