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Structural Transformation of a Multicompartment Micelle Induced by Photo-Switchable Spiropyran–Merocyanine Transition: Dissipative Particle Dynamics Simulation Approach
- Source :
- The Journal of Physical Chemistry - Part B; 20240101, Issue: Preprints
- Publication Year :
- 2024
-
Abstract
- This work highlights the structural transformation of a multicompartment micelle consisting of an amphiphilic A-b-(C-spiropyran) diblock copolymer in water, induced by the photo-switched transition between hydrophobic nonionic spiropyran and hydrophilic zwitterionic merocyanine, using a set of computational methods such as density functional theory (DFT), molecular dynamics (MD) simulation, and dissipated particle dynamics (DPD) simulation. By employing a new computational framework for the Flory–Huggins χ-parameter, which is improved by considering solvation free energy, it is demonstrated that the χ-parameter for a merocyanine–water pair is significantly smaller than that for a spiropyran–water pair, indicating that hydrophobic spiropyran becomes hydrophilic merocyanine through the photo-switched transition. Our computational procedure of χ-parameter calculation is further validated by investigating the deprotonation of syndiotactic and isotatic acrylic acid in water. It is revealed that a reasonable χ-parameter of −0.717 and −1.23 can be calculated from a singly deprotonated syndiotactic and isotatic trimer acrylic acid in water, respectively, which is consistent with the weak acidity of acrylic acid. Finally, using a set of calculated χ-parameters, DPD simulations are performed employing two different block copolymers with two different block lengths: A10-b-(C6-Spiro12) (Micelle I) and A6-b-(C10-Spiro12) (Micelle II), demonstrating that both micelles undergo distinctive inside-out transformations as a function of the block length ratio. Through the structure analysis, it turns out that Micelle I keeps a well-defined core–shell structural feature before and after the transformation, whereas Micelle II loses such structural feature because short Block A is not capable of forming the core of micelle.
Details
- Language :
- English
- ISSN :
- 15206106 and 15205207
- Issue :
- Preprints
- Database :
- Supplemental Index
- Journal :
- The Journal of Physical Chemistry - Part B
- Publication Type :
- Periodical
- Accession number :
- ejs59836096
- Full Text :
- https://doi.org/10.1021/acs.jpcb.2c02269