Structural Features of Polymer Ligand Environments Dramatically Affect the Mechanical and Room-Temperature Self-Healing Properties of Cobalt(II)-Incorporating Polysiloxanes

Abstract

Cobalt(II)-pyridinedicarboxamide-co-polydimethylsiloxane (Co-Py-PDMSs) and cobalt(II)-bipyridinedicarboxamide-co-polydimethylsiloxane (Co-Bipy-PDMSs) polymer−metal complexes were prepared by complexation between Py-PDMSs or Bipy-PDMSs ligands and cobalt(II); the metal content in these complexes varied from 0.09 to 2.41 wt %. The Co II binding patterns (the Co−N Py and Co−O coordination in Co-Py-PDMSs and Co−N Bipy in Co-Bipy-PDMSs) were established by UV−vis and IR methods and by comparison with model Co II complexes exhibiting relevant O,N,O-and N,N-coordination environments, respectively. The mechanical properties of the polymer−metal complexes were controlled by the coordination of Py-PDMSs or Bipy-PDMSs to Co II at various metal-toligand molar ratios (1:(1−6)) and by the variation of the polydimethylsiloxane unit length (M n : 850−900, 5000, or 25 000 g•mol −1 ). Utilization of the chelated Py-PDMSs and Bipy-PDMSs polymer ligands, which are capable of tri-or bidentate binding of Co II , led to (2−4)-fold increases in tensile strength (up to 1.75 MPa) and much higher elongation at break ((2−3)-fold increase up to 2100%) compared with the previously reported Co II -based polymer− ligand systems featuring monodentate ligation entities. Changing the main-chain ligand from Py-PDMSs to Bipy-PDMSs led to an increase in tensile strength of (2−4)-fold in comparison with Py-PDMS and a lower hysteresis (4%). The room temperature selfhealing efficiency was up to 96% for Co-Py-PDMSs and 40% for Co-Bipy-PDMSs, as measured for a polydimethylsiloxane unit with M n = 25 000 g•mol −1 .

Lanthanide(III)-Incorporating Polysiloxanes as Materials for Light-Emitting Devices

“…For example, we employed this feature to obtain a flexible monolith consisting of one red and two green films healed for 4 h at 100 °C. PL spectra of the healed film slightly differ from initial ones (see the Supporting Information), which could be explained by the high temperature-induced ligand exchange and less active heteroleptic complex formation. , …”

“…In the infrared (FTIR) spectrum of Eu-Bipy-PDMS5000 , the amide I ν­(CO) band was shifted from 1658 to 1632 cm –1 in comparison with the parent Bipy-PDMS5000 ligand (Figure S2). According to the literature, ,− this band shift can be attributed to the involvement of the CO group in the coordination.…”

“…PL spectra of the healed film slightly differ from initial ones (see the Supporting Information), which could be explained by the high temperature-induced ligand exchange and less active heteroleptic complex formation. 21,22 2.4. Mechanical Properties of Ln-Bipy-PDMS.…”

Structural Features of Eu3+ and Tb3+-Bipyridinedicarboxamide Complexes

“…According to the refs. [11,[21][22][23], this band shift can be attributed to the involvement of the C=O group in the coordination.…”

A Facile Molding Method of Continuous Fiber-Reinforced Thermoplastic Composites and Its Mechanical Property

“…In order to fabricate C-FRTP with excellent mechanical properties, a new molding method should be developed not only for FRP composites production, but also for a wider range of composites material manufacturing; for example, serving as a new basic method for producing thermoplastic biocomposite [ 8 , 9 ] and other functional composite materials [ 10 , 11 , 12 ]. Currently, there are two main types of technologies being used for FRTP [ 13 , 14 , 15 , 16 ].…”