Gelation Mechanism Revealed in Organometallic Gels: Prevalence of van der Waals Interactions on Oligomerization by Coordination Chemistry

Shaping of nanomaterials is a necessary step for their inclusion in electronic devices and batteries. For this purpose, the formulation of a moldable material including these nanomaterials is desirable. Organomineral gels are a very interesting option, since the components of the nanomaterial itself form a gel without the help of a binder. As a consequence, the properties of the nanomaterial are not diluted by the binder. In this article we studied organometallic gels based on a [ZnCy2] organometallic precursor and a primary alkyl amine which together forms spontaneously gels after few hours. We identified the main parameters controlling the gel properties monitored by rheology and NMR measurements The experiments demonstrate that the gelation time depends on the length of the alkyl chain of the amine and that the gelation mechanism derived firstly from the rigidification of the aliphatic chains of the amine, which takes precedence over the oligomerization of the inorganic backbone. This result highlights that the control of the rheological properties of organometallic gels remains mainly governed by the choice of the amine.

Automated summary

Shaping nanomaterials for electronic devices and batteries requires the formulation of a moldable material that includes these nanomaterials. Organomineral gels, which form a gel without a binder, are a promising option as they do not dilute the properties of the nanomaterial. This study focuses on organometallic gels based on a [ZnCy2] precursor and a primary alkyl amine, exploring the parameters controlling gel properties. The experiments show that gelation time depends on the alkyl chain length of the amine, and that the rigidification of the amine's aliphatic chains has a greater influence on gelation mechanism than the oligomerization of the inorganic backbone.