title: Interface Induced Growth and Transformation of Polymer-Conjugated Proto-Crystalline Phases in Aluminosilicate Hybrids: A Multiple-Quantum (23)Na-(23)Na MAS NMR Correlation Spectroscopy Study.
abstract: Nanostructured materials typically offer enhanced physicochemical properties because of their large interfacial area. In this contribution, we present a comprehensive structural characterization of aluminosilicate hybrids with polymer-conjugated nanosized zeolites specifically grown at the organic-inorganic interface. The inorganic amorphous Al-O-Si framework is formed by alkali-activated low-temperature transformation of metakaoline, whereas simultaneous copolymerization of organic comonomers creates a secondary epoxide network covalently bound to the aluminosilicate matrix. This secondary epoxide phase not only enhances the mechanical integrity of the resulting hybrids but also introduces additional binding sites accessible for compensating negative charge on the aluminosilicate framework. This way, the polymer network initiates growth and subsequent transformation of protocrystalline short-range ordered zeolite domains that are located at the organic-inorganic interface. By applying an experimental approach based on 2D (23)Na-(23)Na double-quantum (DQ) MAS NMR spectroscopy, we discovered multiple sodium binding sites in these protocrystalline domains, in which immobilized Na(+) ions form pairs or small clusters. It is further demonstrated that these sites, the local geometry of which allows for the pairing of sodium ions, are preferentially occupied by Pb(2+) ions during the ion exchange. The proposed synthesis protocol thus allows for the preparation of a novel type of geopolymer hybrids with polymer-conjugated zeolite phases suitable for capturing and storage of metal cations. The demonstrated (23)Na-(23)Na DQ MAS NMR combined with DFT calculations represents a suitable approach for understanding the role of Na(+) ions in aluminositicate solids and related inorganic-organic hybrids, particularly their specific arrangement and clustering at interfacial areas.
authors.affiliation: Institute of Macromolecular Chemistry, Academy of Sciences of the Czech Republic , Heyrovsky sq. 2, 162 06 Prague 6, Czech Republic.
authors.forename: Jiri
authors.initials: J
authors.lastname: Brus
authors.affiliation: Institute of Macromolecular Chemistry, Academy of Sciences of the Czech Republic , Heyrovsky sq. 2, 162 06 Prague 6, Czech Republic.|University of Ottawa , Department of Chemistry and CCRI, 10 Marie Curie Pvt. D'Iorio Hall, Ottawa, Ontario K1N6N5, Canada.
authors.forename: Libor
authors.initials: L
authors.lastname: Kobera
authors.affiliation: Institute of Macromolecular Chemistry, Academy of Sciences of the Czech Republic , Heyrovsky sq. 2, 162 06 Prague 6, Czech Republic.
authors.forename: Martina
authors.initials: M
authors.lastname: Urbanova
authors.affiliation: University of Chemistry and Technology Prague , Technicka 5, Prague, Czech Republic.
authors.forename: Barbora
authors.initials: B
authors.lastname: Doušová
authors.affiliation: University of Chemistry and Technology Prague , Technicka 5, Prague, Czech Republic.
authors.forename: Miloslav
authors.initials: M
authors.lastname: Lhotka
authors.affiliation: University of Chemistry and Technology Prague , Technicka 5, Prague, Czech Republic.
authors.forename: David
authors.initials: D
authors.lastname: Koloušek
authors.affiliation: Institute of Macromolecular Chemistry, Academy of Sciences of the Czech Republic , Heyrovsky sq. 2, 162 06 Prague 6, Czech Republic.
authors.forename: Jiří
authors.initials: J
authors.lastname: Kotek
authors.affiliation: University of Chemistry and Technology Prague , Technicka 5, Prague, Czech Republic.
authors.forename: Pavel
authors.initials: P
authors.lastname: Čuba
authors.affiliation: Institute of Macromolecular Chemistry, Academy of Sciences of the Czech Republic , Heyrovsky sq. 2, 162 06 Prague 6, Czech Republic.
authors.forename: Jiri
authors.initials: J
authors.lastname: Czernek
authors.affiliation: J. Heyrovský Institute of Physical Chemistry, Academy of Sciences of the Czech Republic , Dolejskova 2155/3, 182 23 Prague 8, Czech Republic.
authors.forename: Jiří
authors.initials: J
authors.lastname: Dědeček