Effect of charged segment length on physicochemical properties of core-shell type polyion complex micelles from block ionomers
Effect of charged segment length on physicochemical properties of core-shell type polyion complex micelles from block ionomers
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DOI：
10.1021/ma025737i
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发表时间：
2003-07-01
期刊：
影响因子：
5.5
通讯作者：
Kataoka, K
中科院分区：
文献类型：
--
作者：
Harada, A;Kataoka, K
研究了聚乙二醇-b-聚（α，β-天冬氨酸）[PEG-P（Asp）]与聚乙二醇-b-聚（（L）-赖氨酸）[PEG-P（Lys）]或聚（L）-赖氨酸）[P（Lys）]混合形成的聚离子复合物（PIC）胶束的荷电链段长度对其物理化学性质的影响。由动态和静态光散射测定PIC胶束的流体动力学半径（Rh）和表观重均分子量（M-w，M-app），以计算缔合数、核心半径（R-core）、胶束半径（R-m）、冠层厚度（R-corona）和核心/冠层界面处的PEG密度（PhiPEG）。通过考虑核-壳型PIC胶束中聚合物链的界面能和构象熵之间的平衡，解释了PIC胶束的R-核和Phi（PEG）随嵌段共聚物带电链段长度的变化而发生的变化.这两个参数（R-core和Phi（PEG））之间的平衡似乎在确定胶束尺寸、缔合数以及胶束的M-w、M-app方面发挥着重要作用。此外，Phi（PEG）显示仅取决于PEG-P（Asp）中P（Asp）片段的长度，而与抗衡聚阳离子（PEG-P（Lys）和P（Lys））的组成无关。这一结果表明，Phi（PEG）可能是决定PIC胶束的物理化学特性的最关键的参数。
The influence of the charged segment length on the physicochemical properties of polyion complex (PIC) micelles formed from the mixture of poly(ethylene glycol)-b-poly(alpha,beta-aspartic acid) [PEG-P(Asp)] with poly(ethylene glycol)-b-poly((L)-lysine) [PEG-P(Lys)] or poly((L)-lysine) [P(Lys)] was evaluated in this study. The hydrodynamic radius (Rh) and apparent weight-averaged molecular weight (M-w,M-app) Of the PIC micelles were determined from the dynamic and static light scattering to calculate the association number, core radius (R-core), micellar radius (R-m), corona thickness (R-corona), and PEG density at the core/ corona interface (PhiPEG). Changes in R-core and Phi(PEG) of the PIC micelles with a change in the charged segment length of the block copolymer were explained by considering the balance between the interfacial energy and conformational entropy of polymer strands associated in the core-shell type PIC micelles. Balance among these two parameters (R-core and Phi(PEG)) seems to play a substantial role in determining micellar size, the association number, and, thus, M-w,M-app of the micelles. Furthermore, Phi(PEG) was shown to depend only on the length of the P(Asp) segment in PEG-P(Asp), regardless of the composition of the counter polycations (PEG-P(Lys) and P(Lys)). This result suggests that Phi(PEG) might be the most crucial parameter to determine the physicochemical characteristics of the PIC micelles.