%0 Book Section %1 statphys23_0568 %A Uneyama, T. %B Abstract Book of the XXIII IUPAP International Conference on Statistical Physics %C Genova, Italy %D 2007 %E Pietronero, Luciano %E Loreto, Vittorio %E Zapperi, Stefano %K block copolymer density functional micelle statphys23 theory topic-7 %T Dynamic Density Functional Simulation Study of Morphological Transition Process of Micellar Structures in Amphiphilic Block Copolymer Solutions %U http://st23.statphys23.org/webservices/abstract/preview_pop.php?ID_PAPER=568 %X The amphiphilic block copolymers which consist of hydrophilic subchains and hydrophobic subchains form various micellar structures in selective solvents. The morphologies of micellar structures depend on various parameters such as the strength of the interaction between the monomer and the solvent, volume fraction of polymers, or the architecture of the block copolymer. Although there are many experimental works and theoretical works, the dynamical behaviour of amphiphilic block copolymer micelles are still not completely understood. In this work we study the morphological transition dynamics of micelles in amphiphilic diblock copolymer solutions by using the dynamic density functional theory T. Uneyama, J. Chem. Phys. 126, 114902 (2007). In the density functional theory, the amphiphilic diblock copolymer solution systems are represented by three density fields $\phi_A(r), \phi_B(r), \phi_S(r)$ (subscripts $A,B$ and $S$ represent the hydrophilic monomer, the hydrophobic monomer and the solvent, respectively). The time evolution of the density fields is described by the following dynamic density functional equation. equation \phi_i(\mathbfr,t)t = łeft \phi_i(\mathbfr,t)\zeta \nabla F\\phi_i\\phi_i(r,t) \right + \xi_i(r,t) equation where $\zeta$ is the friction coefficient, $F\\phi_i\$ is the free energy functional for the system, $\xi_i(r,t)$ is the random force which satisfies the fluctuation dissipation type relation. Dynamical simulation can be performed by integrating the dynamic density functional equation numerically. The morphological transition dynamics can be reproduced by changing the Flory-Huggins $\chi$ parameter between the hydrophobic monomer and the solvent. From the simulation results, we can observe that the transition mechanism from spherical micelles to cylindrical micelles and the transition mechanism from cylindrical micelles to spherical micelles are qualitatively different, while the micellar structures are qualitatively the same. In the former mechanism, final cylindrical structures grows by the collision-coalescence type process which is driven by the thermal noise. In the latter mechanism, initial cylindrical structures become unstable and fracture rapidly into spherical micelles.

@incollection{statphys23_0568, abstract = {The amphiphilic block copolymers which consist of hydrophilic subchains and hydrophobic subchains form various micellar structures in selective solvents. The morphologies of micellar structures depend on various parameters such as the strength of the interaction between the monomer and the solvent, volume fraction of polymers, or the architecture of the block copolymer. Although there are many experimental works and theoretical works, the dynamical behaviour of amphiphilic block copolymer micelles are still not completely understood. In this work we study the morphological transition dynamics of micelles in amphiphilic diblock copolymer solutions by using the dynamic density functional theory [T. Uneyama, {\em J. Chem. Phys.} {\bf 126}, 114902 (2007)]. In the density functional theory, the amphiphilic diblock copolymer solution systems are represented by three density fields $\phi_A(\mathbf{r}), \phi_B(\mathbf{r}), \phi_S(\mathbf{r})$ (subscripts $A,B$ and $S$ represent the hydrophilic monomer, the hydrophobic monomer and the solvent, respectively). The time evolution of the density fields is described by the following dynamic density functional equation. \begin{equation} \frac{\partial \phi_i(\mathbf{r},t)}{\partial t} = \nabla \cdot \left[ \frac{\phi_i(\mathbf{r},t)}{\zeta} \nabla \frac{\delta F[\{\phi_i\}]}{\delta \phi_i(\mathbf{r},t)} \right] + \xi_i(\mathbf{r},t) \end{equation} where $\zeta$ is the friction coefficient, $F[\{\phi_i\}]$ is the free energy functional for the system, $\xi_i(\mathbf{r},t)$ is the random force which satisfies the fluctuation dissipation type relation. Dynamical simulation can be performed by integrating the dynamic density functional equation numerically. The morphological transition dynamics can be reproduced by changing the Flory-Huggins $\chi$ parameter between the hydrophobic monomer and the solvent. From the simulation results, we can observe that the transition mechanism from spherical micelles to cylindrical micelles and the transition mechanism from cylindrical micelles to spherical micelles are qualitatively different, while the micellar structures are qualitatively the same. In the former mechanism, final cylindrical structures grows by the collision-coalescence type process which is driven by the thermal noise. In the latter mechanism, initial cylindrical structures become unstable and fracture rapidly into spherical micelles.}, added-at = {2007-06-20T10:16:09.000+0200}, address = {Genova, Italy}, author = {Uneyama, T.}, biburl = {https://www.bibsonomy.org/bibtex/2a6a874c02011ed7e224e97447bbb9bb3/statphys23}, booktitle = {Abstract Book of the XXIII IUPAP International Conference on Statistical Physics}, editor = {Pietronero, Luciano and Loreto, Vittorio and Zapperi, Stefano}, interhash = {6fb8c8e745afd39ec6324b70568622aa}, intrahash = {a6a874c02011ed7e224e97447bbb9bb3}, keywords = {block copolymer density functional micelle statphys23 theory topic-7}, month = {9-13 July}, timestamp = {2007-06-20T10:16:23.000+0200}, title = {Dynamic Density Functional Simulation Study of Morphological Transition Process of Micellar Structures in Amphiphilic Block Copolymer Solutions}, url = {http://st23.statphys23.org/webservices/abstract/preview_pop.php?ID_PAPER=568}, year = 2007 }