Efficient metal-free strategies for polymerization of a sterically hindered ionic monomer through the application of hard confinement and high pressure

Paulina Maksym; Magdalena Tarnacka; Andrzej Dzienia; Kamila Wolnica; Mateusz Dulski; Karol Erfurt; Anna Chrobok; Andrzej Zięba; Agnieszka Brzózka; Grzegorz Sulka; Rafał Bielas; Kamil Kaminski; Marian Paluch

doi:10.1039/c8ra09242g

Efficient metal-free strategies for polymerization of a sterically hindered ionic monomer through the application of hard confinement and high pressure

RSC Adv. 2019 Feb 21;9(11):6396-6408. doi: 10.1039/c8ra09242g. eCollection 2019 Feb 18.

Authors

Paulina Maksym^{1

2}, Magdalena Tarnacka^{1

2}, Andrzej Dzienia^{2

3}, Kamila Wolnica^{1

2}, Mateusz Dulski^{2

4}, Karol Erfurt⁵, Anna Chrobok⁵, Andrzej Zięba⁶, Agnieszka Brzózka⁷, Grzegorz Sulka⁷, Rafał Bielas⁸, Kamil Kaminski^{1

2}, Marian Paluch^{1

2}

Affiliations

¹ Institute of Physics, University of Silesia ul. 75 Pulku Piechoty 1 41-500 Chorzow Poland paulina.maksym@smcebi.edu.pl kamil.kaminski@smcebi.edu.pl +48323497610.
² Silesian Center of Education and Interdisciplinary Research, University of Silesia ul. 75 Pulku Piechoty 1A 41-500 Chorzow Poland.
³ Institute of Chemistry, University of Silesia ul. Szkolna 9 40-007 Katowice Poland.
⁴ Institute of Materials Science, University of Silesia ul. 75 Pulk Piechoty 1 41-500 Chorzow Poland.
⁵ Department of Chemical Organic Technology and Petrochemistry, Silesian University of Technology ul. Krzywoustego 4 44-100 Gliwice Poland.
⁶ Department of Organic Chemistry, School of Pharmacy with the Division of Laboratory Medicine in Sosnowiec, Medical University of Silesia in Katowice ul. Jagiellońska 4 41-200 Sosnowiec Poland.
⁷ Department of Physical Chemistry and Electrochemistry, Faculty of Chemistry, Jagiellonian University ul. Gronostajowa 2 30-387 Krakow Poland.
⁸ Department of Physical Chemistry and Technology of Polymers, Faculty of Chemistry, Silesian University of Technology ul. M. Strzody 9 44-100 Gliwice Poland.

Abstract

In this paper, we have studied the effect of both hard confinement (nanoporous membranes treated as nanoreactors) and high pressure (compression of system) on the progress of free-radical (FRP) and reversible addition-fragmentation chain transfer (RAFT) polymerizations of selected hardly polymerizable, sterically hindered imidazolium-based ionic monomer 1-octyl-3-vinylimidazolium bis(trifluoromethanesulfonyl)imide ([OVIM][NTf₂]). These two innovative approaches, affecting (in a different way) the free volume of the polymerizing system, allows the reduction of the number of toxic substrates/catalysts, satisfying the requirement of green chemistry. It was found that at both conditions (high compression and confinement) the polymerizability of monomer, as well as the control over the reaction and the properties of the produced polyelectrolytes, have increased significantly. However, it should be added that there were noticeable differences between FRP carried out under confinement and at high pressures. Interestingly, by appropriate variation in thermodynamic conditions, it was possible to synthesize polymers of moderate molecular weight (M _n ∼ 58 kg mol^-1) and relatively low dispersity (Đ ∼ 1.7); while for the reaction performed within AAO pores of varying diameter (d = 35 nm and d = 150 nm), macromolecules of higher M _n but slightly broader dispersity indices (Đ ∼ 2.2-2.7) were recovered. On the other hand, RAFT polymerization carried out under confinement and at elevated pressures yielded polymers with well-defined properties. Noteworthy is also the fact that nanopolymerization leads to polymers of comparable M _n to those obtained at high-pressure studies but at significantly shorter reaction time (t ∼ 2 hours). We believe that the presented data clearly demonstrated that both examined approaches (the compression and application of alumina templates, treated as nanoreactors) could be successfully used as additional driving forces to polymerize sterically hindered monomers and produce well-defined polymers in relatively short times. At the same time, it should be mentioned that both proposed polymerization methods enabled us to omit the addition of metal-based initiators/catalysts, which seem to be a crucial step towards further development of the alternative green synthesis of polyelectrolytes in the future.