Solubilization of charged porphyrins in interpolyelectrolyte complexes: A computer study.

0540531 - ÚCHP 2022 RIV CH eng J - Journal Article
Šindelka, Karel - Limpouchová, Z. - Procházka, K.
Solubilization of charged porphyrins in interpolyelectrolyte complexes: A computer study.
Polymers. Roč. 13, č. 4 (2021), č. článku 502. E-ISSN 2073-4360
Institutional support: RVO:67985858
Keywords : computer simulations * porphyrin * electrostatic co-assembly
OECD category: Physical chemistry
Impact factor: 4.967, year: 2021
Method of publishing: Open access
https://www.mdpi.com/2073-4360/13/4/502

Using coarse-grained dissipative particle dynamics (DPD) with explicit electrostatics, we performed (i) an extensive series of simulations of the electrostatic co-assembly of asymmetric oppositely charged copolymers composed of one (either positively or negatively charged) polyelec-trolyte (PE) block A and one water-soluble block B and (ii) studied the solubilization of positively charged porphyrin derivatives (P+ ) in the interpolyelectrolyte complex (IPEC) cores of co-assembled nanoparticles. We studied the stoichiometric mixtures of 137 A+10B25 and 137 A−10B25 chains with moderately hydrophobic A blocks (DPD interaction parameter aAS = 35) and hydrophilic B blocks (aBS = 25) with 10 to 120 P+ added (aPS = 39). The P+ interactions with other components were set to match literature information on their limited solubility and aggregation behavior. The study shows that the moderately soluble P+ molecules easily solubilize in IPEC cores, where they partly replace PE+ and electrostatically crosslink PE− blocks. As the large P+ rings are apt to aggregate, P+ molecules aggregate in IPEC cores. The aggregation, which starts at very low loadings, is promoted by increasing the number of P+ in the mixture. The positively charged copolymers repelled from the central part of IPEC core partially concentrate at the core-shell interface and partially escape into bulk solvent depending on the amount of P+ in the mixture and on their association number, AS . If AS is lower than the ensemble average 〈AS 〉n, the copolymer chains released from IPEC preferentially concentrate at the core-shell interface, thus increasing AS, which approaches 〈AS 〉n . If AS > 〈AS 〉n, they escape into the bulk solvent.
Permanent Link: http://hdl.handle.net/11104/0318159