Effect of Metal-Ligand Coordination Complexes on Molecular Dynamics and Structure of Cross-Linked Poly(dimethylosiloxane)
| Autor: | Izabela Bobowska, Paulina Maczugowska, Katarzyna M. Błażewska, Angelika Wrzesińska, Aleksandra Wypych-Puszkarz, Joanna Małolepsza |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2020 |
| Předmět: |
chemistry.chemical_classification
Materials science Polymers and Plastics Ligand fragility index General Chemistry Polymer Dielectric PDMS metal-ligand complexes broadband dielectric spectroscopy Article molecular dynamics lcsh:QD241-441 Crystallography Bipyridine chemistry.chemical_compound Molecular dynamics Differential scanning calorimetry lcsh:Organic chemistry chemistry constrained amorphous phase Molecule glass transition Glass transition |
| Zdroj: | Polymers Volume 12 Issue 8 Polymers, Vol 12, Iss 1680, p 1680 (2020) |
| ISSN: | 2073-4360 |
| DOI: | 10.3390/polym12081680 |
| Popis: | Poly(dimethylosiloxane) (PDMS) cross-linked by metal-ligand coordination has a potential functionality for electronic devices applications. In this work, the molecular dynamics of bipyridine (bpy)&ndash PDMS-MeCl2 (Me: Mn2+, Fe2+, Ni2+, and Zn2+) are investigated by means of broadband dielectric spectroscopy and supported by differential scanning calorimetry and density functional theory calculations. The study of molecular motions covered a broad range of temperatures and frequencies and was performed for the first time for metal-ligand cross-linked PDMS. It was found that the incorporation of bpy moieties into PDMS chain prevents its crystallization. The dielectric permittivity of studied organometallic systems was elevated and almost two times higher (&epsilon &prime ~4 at 1 MHz) than in neat PDMS. BpyPDMS-MeCl2 complexes exhibit slightly higher glass transition temperature and fragility as compared to a neat PDMS. Two segmental type relaxations (&alpha and &alpha ac) were observed in dielectric studies, and their origin was discussed in relation to the molecular structure of investigated complexes. The &alpha ac relaxation was observed for the first time in amorphous metal-ligand complexes. It originates from the lower mobility of PDMS polymer chains, which are immobilized by metal-ligand coordination centers via bipyridine moieties. |
| Databáze: | OpenAIRE |
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