固体状態のブロックコポリマーの超分子集積は,インクルージョン結晶の選択的形成によって支援されます
Silvia Bracco1, Angiolina Comotti, Lisa Ferretti
1Department of Materials Science, University of Milano Bicocca, Via R. Cozzi 53, 20125 Milano, Italy.
Journal of the American Chemical Society
|May 20, 2011
まとめ
研究者らは,宿主分子とトライブロック共ポリマーを使用して,組織化された2Dナノ結晶を作成しました. この超分子自己組み立ては,エチレン酸化物ブロックを選択的に含み,非共性相互作用によって堅固な材料を形成します.
科学分野:
- マテリアルサイエンス 材料科学
- 超分子化学 超分子化学
- ポリマーサイエンスの科学
背景:
- ポリエチレン酸化物-b-プロピレン酸化物-b-エチレン酸化物 (EO) のようなトリブロック共ポリマー (PO) は,多用途のビルディングブロックを提供します.
- 超分子自己組み立ては,非共性相互作用を通じて秩序のある材料を作成するための経路を提供します.
- 包摂化合物を形成できる宿主分子は,ゲスト分子の組み立てを指揮することができます.
研究 の 目的:
- トライブロックコポリマーと宿主分子の超分子自己組成を調査する.
- 定義された構造と性質を持つ2Dナノ結晶を形成する.
- 自己組み立てプロセスを支配する原動力と相互作用を理解する.
主な方法:
- 溶剤のない機械化学的アプローチと自己組み立てのための熱処理.
- 構造形成を監視するために,インサイトシンクロトロンX線 difraktion.
- 固体NMR ((1) H-(13) C, (1) H MAS) でホスト・ゲストの相互作用とトポロジーを探求する.
- Ab initio計算 (HF-GIAO/DGDZVP) で磁気感受性と分子間相互作用を分析する.
主要な成果:
- エチレン酸化物 (EO) ブロックを宿主分子の内部に選択的に挿入することによって,インクルージョン2Dナノ結晶の形成.
- プロピレン酸化物 (PO) ブロックの相分離により,交互に結晶状のラメラと無形層が形成されます.
- 協力的な非共性分子間相互作用とCH··π相互作用を駆動力として実証.
- 親密な宿主-ゲストの相互作用と堅固な超分子構造の確認.
結論:
- ブロックコポリマーとクラトラート形成宿主分子を組み合わせた戦略により,組織化された材料の製造が可能になります.
- 選択的非共振相互作用は,複雑なポリマー構造の自己組み立てを指示する鍵です.
- その結果生じる超分子構造は,特定のホスト-ゲストの相互作用により,強化された強度を示します.
関連する概念動画
Characteristics and Nomenclature of Copolymers
Copolymers are the products obtained from the polymerization of multiple monomer species. So, in a polymer chain itself, there can be multiple repeating units that come from different monomers. The process of synthesizing a polymer from different monomer species is called copolymerization. When two monomers are involved, the polymer is known as a bipolymer. Polymers with three and four monomers are termed terpolymers and quaterpolymers, respectively. Figure 1 depicts the copolymerization of...
Polymer Classification: Crystallinity
Unlike ionic or small covalent molecules, polymers do not form crystalline solids due to the diffusion limitations of their long-chain structures. However, polymers contain microscopic crystalline domains separated by amorphous domains.
Crystalline domains are the regions where polymer chains are aligned in an orderly manner and held together in proximity by intermolecular forces. For example, chains in the crystalline domains of polyethylene and nylon are bound together by van der Waals...
Crystalline domains are the regions where polymer chains are aligned in an orderly manner and held together in proximity by intermolecular forces. For example, chains in the crystalline domains of polyethylene and nylon are bound together by van der Waals...
Recrystallization: Solid–Solution Equilibria
Recrystallization is a purification technique used to separate impurities from solid compounds. In this technique, no chemical reactions occur. Instead, it exploits physical properties only, specifically, the solubility differences between the desired compound and impurities, either at a single temperature or at different temperatures, and under other selected conditions. The solid-solution equilibrium (solubility equilibrium) of each component in the solution represents a binary phase...
Crystal Growth: Principles of Crystallization
Crystallization is a phase transformation process in which crystals are precipitated from a supersaturated solution or formed from other sources. During crystallization, atoms or molecules arrange themselves into a well-defined, rigid crystal lattice to minimize energy.
Initiating crystallization involves manipulating the concentration of the solute and the temperature of the solution. Since crystal growth occurs when the ratio of concentration and solubility of the solute in the solvent – the...
Initiating crystallization involves manipulating the concentration of the solute and the temperature of the solution. Since crystal growth occurs when the ratio of concentration and solubility of the solute in the solvent – the...
Precipitation Processes
The experimental conditions in a gravimetric analysis should be optimized to maximize the particle size and purity of the obtained precipitate. Ideally, the concentration of the precipitating reagent should be low with effective stirring to maintain low relative supersaturation for the growth of large crystals. In homogeneous precipitation, the precipitant is slowly generated by a chemical reaction in the solution to avoid local reagent excesses. For example, urea decomposes gradually to...
Cationic Chain-Growth Polymerization: Mechanism
The cationic polymerization mechanism consists of three steps: initiation, propagation, and termination. In the initiation step of the polymerization process, the π bond of a monomer gets protonated by the Lewis acid catalyst, which is formed from boron trifluoride and water. The protonation of the π bond generates a carbocation stabilized by the electron‐donating group. In the propagation step, the π bond of the second monomer acts as a nucleophile and attacks the generated carbocation,...


