Thirty years since J. Davidovits introduced geopolymers considered now as hypo-crystalline materials within the mers-framework and the effect of oxygen binding: a review

The development of new materials called geopolymers is described, which at the turn of the nineties brought a new state of the art in material design through the so-called wet process resulting in a specific amorphous state. The classical configuration of glasses prepared by quenching is used for a joint appraisal and judgment. We can use the comparison and description of the known form of organic polymers with the so-called mers-structure. The formation involves a sol–gel polycondensation chemical reaction also known in the case of organic polymers. The formation is described using aluminosilicate oxide in IV-fold coordination with alkaline polysilicates to form polymeric Si–O–Al chains through amorphous to semi- and hypo-crystalline three-dimensional silico-aluminate structures. The revision of structural units and their interconnection is evaluated, and it turns out that the common factor of the multiparty description is the existence of bridging and non-bridging oxygen. The review provides a detailed overview of opinion while reminding that the historical origin of the field falls within the purview of the JTAC journal.