Rationalizing the Phase Behavior of Triblock Copolymers through Experiments and Molecular Simulations

abstract

In this paper, we develop a new coarse-grained model, under the MARTINI framework, for Pluronic block copolymers that is able to describe the self-assembly mechanism and reproduce experimental micelle sizes and shapes. Previous MARTINI-type Pluronic models were unable to produce realistic micelles in aqueous solution, and thus our model represents a marked improvement over existing approaches. We then applied this model to understand the effects of polymer structure on the cloud point temperature measured experimentally for a series of Pluronics, including both normal and reverse copolymers. It was observed that high polyoxypropylene glycol content leads to dominant hydrophobic interactions and a lower cloud point temperature, while high hydrophilic polyoxyethylene glycol content shields the micelles against aggregation and hence leads to a higher cloud point temperature. As the concentration increases, the effect of polymer architecture (normal versus reverse) starts to dominate, with reverse Pluronics showing a lower cloud point temperature. This was shown to be due to the increased formation of cross-links between neighboring micelles in these systems, which promote micelle aggregation. Our results shed new light on these fascinating systems and open the door to increased control of their thermal responsive behavior.

keywords

COARSE-GRAINED MODEL; POLY(ETHYLENE OXIDE); DYNAMICS SIMULATIONS; FORCE-FIELD; POLY(PROPYLENE OXIDE); AQUEOUS-SOLUTIONS; BLOCK-COPOLYMERS; IONIC LIQUIDS; COMPUTER-SIMULATION; TEMPLATED SYNTHESIS

subject category

Chemistry; Science & Technology - Other Topics; Materials Science

authors

Perez-Sanchez, G; Vicente, FA; Schaeffer, N; Cardoso, IS; Ventura, SPM; Jorge, M; Coutinho, JAP

Groups

G4 - Renewable Materials and Circular Economy
G5 - Biomimetic, Biological and Living Materials
G6 - Virtual Materials and Artificial Intelligence

Projects

CICECO - Aveiro Institute of Materials (UID/CTM/50011/2019)

Projeto de Investigação Exploratória: Sónia Patricia Marques Ventura (IF/00402/2015)

Battery Recycling – Achieving Rare Earth Separation (BATRES)

acknowledgements

This work was developed within the scope of the project CICECO-Aveiro Institute of Materials, FCT ref. UID/CTM/50011/2019, financed by national funds through the FCT/MCTES, and when appropriate cofinanced by FEDER under the PT2020 Partnership Agreement. The authors are also grateful for the national fund through the Portuguese Foundation for Science and Technology (FCT) for the doctoral grant SFRH/BD/101683/2014 of F.A.V. S.P.M.V. acknowledges FCT for the Contract IF/00402/2015 under the Investigador FCT 2015. G.P.S. acknowledges the research contract under Project CENTRO-01-0145-FEDER-000005: SusPhotoSolutions: SolucOes Fotovoltaicas Susten6veis. N.S. would like to acknowledge financial support from the BATREARES project (ERA-MIN/0001/2015) funded by ADEME and FCT.