セレノフェン-チオフェンの共ポリメリゼーションによる結合ポリマーの相分離と光学特性を制御する
Jon Hollinger1, Ashlee A Jahnke, Neil Coombs
1Department of Chemistry, University of Toronto, 80 St. George Street, Toronto, Ontario, Canada M5S 3H6.
Journal of the American Chemical Society
|June 8, 2010
まとめ
新型セレノフェン-チオフェンブロック共ポリマーは,統計的共ポリマーとは異なる特性を示しています. これらの結合ブロックコポリマーは相分離を示し,新しい光電子学アプリケーションの道を開く.
科学分野:
- マテリアルサイエンス 材料科学
- ポリマー化学のポリマー化学について
- オーガニック・エレクトロニクス
背景:
- 結合ブロックコポリマーは,統計的コポリマーと比較してユニークな性質を提供します.
- 自己組み立てと相分離の理解は,高度な材料の設計に不可欠です.
研究 の 目的:
- 新型セレノフェン-チオフェンブロックコポリマーを合成し,特徴づけること.
- これらの共ポリマーの固体状態の性質と自己組み立て行動を調査するために.
- 光電子学におけるそれらの潜在的な応用を探求する.
主な方法:
- セレノフェン-チオフェンブロックコポリマーの合成.
- スペクトル分析 (UV-Vis吸収).
- スキャニング・トランスミッション電子顕微鏡 (STEM) とトポグラフィック・エレメンタル・マッピングを用いた固体状態の特徴化.
主要な成果:
- ブロックコポリマーには,広く赤にシフトした吸収スペクトルが示された.
- セレノフェンまたはチオフェンに富んだ明確な相分離ドメインが観察されました.
- 異なるヘテロサイクルのブロック間の好ましい関連性の証拠が発見され,基本的差異によって引き起こされました.
結論:
- セレノフェン-チオフェンブロック共ポリマーは,ユニークな相分離構造を示します.
- 元素の差異は,これらの結合ポリマーにおける相分離を制御する.
- これらの新しい材料は,多様な光電子機器のアプリケーションに期待を寄せている.
関連する概念動画
01:17Thermal Electrocyclic Reactions: Stereochemistry
The stereochemistry of electrocyclic reactions is strongly influenced by the orbital symmetry of the polyene HOMO. Under thermal conditions, the reaction proceeds via the ground-state HOMO.
Selection Rules: Thermal Activation
Conjugated systems containing an even number of π-electron pairs undergo a conrotatory ring closure. For example, thermal electrocyclization of (2E,4E)-2,4-hexadiene, a conjugated diene containing two π-electron pairs, gives trans-3,4-dimethylcyclobutene.
Selection Rules: Thermal Activation
Conjugated systems containing an even number of π-electron pairs undergo a conrotatory ring closure. For example, thermal electrocyclization of (2E,4E)-2,4-hexadiene, a conjugated diene containing two π-electron pairs, gives trans-3,4-dimethylcyclobutene.
01:13Olefin Metathesis Polymerization: Overview
Recently, the development of olefin metathesis polymerization advanced the field of polymer synthesis. Simply put, the reorganization of substituents on their double bonds between two olefins in the presence of a catalyst is known as the olefin metathesis reaction. The use of metathesis reaction for polymer synthesis is called olefin metathesis polymerization.
Ruthenium-based Grubbs catalyst is the most commonly used catalyst for olefin metathesis polymerization. Grubbs catalyst consists of a...
Ruthenium-based Grubbs catalyst is the most commonly used catalyst for olefin metathesis polymerization. Grubbs catalyst consists of a...
01:26Photochemical Electrocyclic Reactions: Stereochemistry
The absorption of UV–visible light by conjugated systems causes the promotion of an electron from the ground state to the excited state. Consequently, photochemical electrocyclic reactions proceed via the excited-state HOMO rather than the ground-state HOMO. Since the ground- and excited-state HOMOs have different symmetries, the stereochemical outcome of electrocyclic reactions depends on the mode of activation; i.e., thermal or photochemical.
Selection Rules: Photochemical Activation
Selection Rules: Photochemical Activation
01:16Olefin Metathesis Polymerization: Ring-Opening Metathesis Polymerization (ROMP)
Ring-opening metathesis polymerization or ROMP involves strained cycloalkenes as starting materials. The mechanism of ROMP proceeds by reacting cycloalkene with Grubbs catalyst to give metallacyclobutane intermediate which undergoes a ring-opening reaction to form new carbene. The new carbene reacts with another molecule of cycloalkene. Repetition of these steps leads to the formation of an unsaturated open-chain polymer product. All these steps are reversible, however, relieving the ring...
01:26Thermal and Photochemical Electrocyclic Reactions: Overview
Electrocyclic reactions are reversible reactions. They involve an intramolecular cyclization or ring-opening of a conjugated polyene. Shown below are two examples of electrocyclic reactions. In the first reaction, the formation of the cyclic product is favored. In contrast, in the second reaction, ring-opening is favored due to the high ring strain associated with cyclobutene formation.
00:53Olefin Metathesis Polymerization: Acyclic Diene Metathesis (ADMET)
Acyclic diene metathesis polymerization or ADMET polymerization involves cross-metathesis of terminal dienes, such as 1,8-nonadiene, to give linear unsaturated polymer and ethylene. As ADMET is a reversible process, the formed ethylene gas must be removed from the reaction mixture to complete the polymerization process.
Similar to cross-metathesis, ADMET also involves the formation of metallacyclobutane intermediate by [2+2] cycloaddition of one of the double bonds of a terminal diene with...
Similar to cross-metathesis, ADMET also involves the formation of metallacyclobutane intermediate by [2+2] cycloaddition of one of the double bonds of a terminal diene with...