独特的 toroidal 形态从组合和序列控制的triblock 共聚合物
Zhiyun Chen1, Honggang Cui, Kelly Hales
1Center for Materials Innovation and Department of Chemistry, Washington University in Saint Louis, Saint Louis, Missouri 63130, USA.
Journal of the American Chemical Society
|June 16, 2005
概括
烯酸,甲基烯酸盐和烯块的序列显著影响了triblock共聚合物的自我组装,形成独特的 toroidal 结构. 块共聚合物序列对于形成特定的超分子组件至关重要.
科学领域:
- 聚合物科学 聚合物科学
- 材料科学 材料科学 材料科学
- 超分子化学 超分子化学
背景情况:
- 特里布洛克共聚物自组装成复杂的形态.
- 了解控制自组装的因素是材料设计的关键.
研究的目的:
- 为了研究状超分子组合在烯酸,甲基烯酸和烯三块化共聚合物中形成的机制.
- 为了确定块共聚合物组成和序列对自组装的影响.
主要方法:
- 四个区块共聚合物的合成和表征:PAA99-b-PMA73-b-PS66,PAA99-b-PS76-b-PMA62,PAA99-b-PMA155和PAA99-b-PS133.3的PAA99-b-PS76-b-PMA62,PAA99-b-PMA155和PAA99-b-PS133.3的PAA99-b-PS76-b-PMA62,PAA99-b-PMA155和PAA99-b-PS133.3的PAA99-b-PS76-b-PMA66,PAA99-b-PS76-b-PMA66,PAA99-b-PMA155和PAA99-b-PS133.3的PAA99-b-PS66,PAA99-b-PS76-b-PMA67,PAA99-b-PMA155,以及PAA99-b-PS133,PAA99-b-PMA155,PAA99-b-PMA155和PAA99-b-PS7
- 溶液状态自组合研究在不同四二/水组合与2.2'-(乙烯二氧化物) bis(乙烯胺).
- 使用传输电子显微镜确定形态.
主要成果:
- 状超分子组是由PAA99-b-PMA73-b-PS66.6形成的.
- 具有可比性疏水细分 (PMA或PS) 的双块共聚合物没有形成状结构.
- 一种具有反向顺序的疏水块 (PAA99-b-PS76-b-PMA62) 的triblock共聚合物也未能形成 toroidal 组件.
结论:
- 烯酸,甲基烯酸和烯块的特定序列对于形成独特的状超分子组件至关重要.
- 区块共聚合物序列在决定自组装结果方面,比疏水性段的总长度发挥更重要的作用.
相关概念视频
Overview of Transposition and Recombination
Transposons make up a significant part of genomes of various organisms. Therefore, it is believed that transposition played a major evolutionary role in speciation by changing genome sizes and modifying gene expression patterns. For example, in bacteria, transposition can lead to conferring antibiotic resistance. Movement of transposable elements within the genetic pool of pathogenic bacteria can aid in transfer of antibiotic-resistant genetic elements. In eukaryotes, transposons can carry out...
LTR Retrotransposons
LTR retrotransposons are class I transposable elements with long terminal repeats flanking an internal coding region. These elements are less abundant in mammals compared to other class I transposable elements. About 8 percent of human genomic DNA comprises LTR retrotransposons. Some of the common examples of LTR retrotransposons are Ty elements in yeast and Copia elements in Drosophila.
The internal coding region of LTR retrotransposons and their mechanism of transposition closely resembles a...
The internal coding region of LTR retrotransposons and their mechanism of transposition closely resembles a...
Block Diagram Reduction
The process of deriving the transfer function of a control system often involves reducing its block diagram to a single block. This simplification can be achieved through a series of strategic operations, including relocating branch points and comparators. These operations preserve the overall function of the system while allowing for easier manipulation and combination of blocks.
The first step in this process is the identification and relocation of a branch point. A branch point, where a...
The first step in this process is the identification and relocation of a branch point. A branch point, where a...
Line Protection with Impedance Relays
Coordinating time-delay overcurrent relays in complex radial systems and directional overcurrent relays in multi-source transmission loops can be challenging. Impedance relays address these issues by responding to the voltage-to-current ratio, specifically measuring the apparent impedance of a line. These relays become more sensitive during faults as current increases and voltage decreases, thereby reducing the apparent impedance.
Under normal conditions, low load currents keep the measured...
Under normal conditions, low load currents keep the measured...
Differential Relays
Differential relays are used to protect generators, buses, and transformers by comparing electrical quantities at different points. When a fault occurs, the difference in current between the two points triggers the relay to operate, opening the circuit breaker. Under normal conditions, the current entering (i1) and leaving (i2) a generator are equal. When a fault occurs, however, these currents become unequal, and the difference current flows in the relay operating coil, causing the relay to...
Repressible Operon: trp Operon
The trp operon in Escherichia coli exemplifies a repressible operon. It regulates the synthesis of tryptophan through repressor-mediated transcriptional control and attenuation. This dual regulatory mechanism ensures tryptophan biosynthesis occurs only when needed, conserving cellular resources.Structure of the trp OperonThe trp operon consists of five structural genes (trpE, trpD, trpC, trpB, and trpA) that encode enzymes for tryptophan biosynthesis. These genes are transcribed as a single...


