線形ブロックコポリマー溶液における六角密集球の出現
Cheng Zhang1, Daniel L Vigil, Dan Sun
1Australian Institute for Bioengineering and Nanotechnology and ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, University of Queensland, Brisbane, Queensland 4072, Australia.
Journal of the American Chemical Society
|August 27, 2021
まとめ
研究者らは,特定の線形ブロックコポリマーに純粋な六角密集球 (HCP) を発見した. この発見は,このような資料の HCP 段階へのアクセスに関する以前の仮定に異議を唱えます.
科学分野:
- ポリマー科学
- 材料科学
- 柔らかい物質の物理
背景:
- 六角密集 (HCP) 球相は理論的には安定しているが,小さな自由エネルギー差により他の相と共存することが多い.
- 純粋なHCP領域を達成するには,通常複雑な処理または混合技術が必要です.
研究 の 目的:
- 新しい線形ブロックコポリマー溶液の HCP球の発見を報告する
- HCPのフェーズ形成と安定性の条件とメカニズムを調査する.
主な方法:
- 線形ブロックコポリマーと特定のポリマーブロック (ポリ,2,2,2-トリフオロエチルアクリル酸) とポリ,2-ドデシルアクリル酸) またはポリ,4-ドデシルアクリル酸) の合成
- Aブロックの体積分数の範囲における相行動の特徴化.
- 段階形成の運動と可逆性の分析
- 段階安定性を理解するための自己一貫したフィールド理論の計算.
主要な成果:
- 純粋なHCP球は,4DF二重ブロックおよびF4DF三重ブロック共ポリマーで成功裏に合成されました.
- HCPフェーズは,Aブロック量分数の有意な範囲 (約0. 25 - 0. 30) で観察されました.
- F4DFトライブロックでは,HCP相が逆転して形成され,平衡状態を示す.
- HCPの形成は,超冷却された液体または柔らかい固体から直接発生し,中間準結晶相を回避した.
- モラー質量分散度 (Đ) は,HCPの安定性にとって重要であり,低分散度 (例えば, Đ = 1.04) はHCPフェーズに好意的であることが判明した.
結論:
- この研究は,複雑な処理なしに線形ブロックコポリマーで純粋なHCP球を得るための新しい経路を示しています.
- この発見は,低モラー質量分散がHCP段階の安定化に果たす重要な役割を強調しています.
- この研究は従来の理解に挑戦し,複雑なポリマー構造の制御された合成の可能性を開きます.
関連する概念動画
Polymer Classification: Crystallinity
3.4K
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...
3.4K
Metallic Solids
19.6K
Metallic solids such as crystals of copper, aluminum, and iron are formed by metal atoms. The structure of metallic crystals is often described as a uniform distribution of atomic nuclei within a “sea” of delocalized electrons. The atoms within such a metallic solid are held together by a unique force known as metallic bonding that gives rise to many useful and varied bulk properties.
All metallic solids exhibit high thermal and electrical conductivity, metallic luster, and malleability....
All metallic solids exhibit high thermal and electrical conductivity, metallic luster, and malleability....
19.6K
Characteristics and Nomenclature of Copolymers
2.9K
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...
2.9K
Molecular Weight of Step-Growth Polymers
2.5K
Step growth polymerization involves bi or multifunctional monomers. Bifunctional monomers react to form linear step growth polymers, whereas multifunctional monomers react to form non-linear or branched polymers.
As the step-growth polymerization involves step-wise condensation of monomers, the molecular weight also builds up eventually. Consequently, high molecular weight polymers are obtained at the late stages of the polymerization, where 99% of monomers have been consumed.
The extent of the...
As the step-growth polymerization involves step-wise condensation of monomers, the molecular weight also builds up eventually. Consequently, high molecular weight polymers are obtained at the late stages of the polymerization, where 99% of monomers have been consumed.
The extent of the...
2.5K
Polymer Classification: Architecture
3.3K
Polymers are classified as linear or branched on the basis of their chain architecture. The polymer chains in linear polymers have a long chain-like structure with minimal to no branching at all. Even if a polymer features large substituent groups on the monomer, which appear as branches to the skeleton, it is not considered a branched polymer. A branched polymer contains secondary polymer chains that arise from the main polymer chain. The branching occurs when the polymer growth shifts from...
3.3K
Radical Chain-Growth Polymerization: Chain Branching
2.1K
The skeletal structure of polymers synthesized via radical polymerization is always branched. For example, the polymerization of ethylene by radical polymerization results in a low-density grade of polyethylene with a heavily branched skeletal structure. Here, the radical site abstracts hydrogen from the growing chain, and the radical site shifts from the end (a primary carbon center) to anywhere within the growing chain (a secondary carbon center). Consequently, the part of the chain from the...
2.1K


