Properties

Flexibility


Marshmallow-like gels are very soft materials. They are compressible and bendable without any destruction of their structure and quickly recover their original shape after removing stress.[1] The flexibility is derived from their organic-inorganic micrometer-scale structure. Mechanical properties of marshmallow-like gels derived from methyltrimethoxysilane and dimethyldimethoxysilane as co-precursors do not change in wide temperature range (from −130 to 320 °C). Even more, these gel have some flexibility in liquid nitrogen.[2]

Superhydrophobicity


Marshmallow-like gels have strong hydrophibicity.[2] This property is caused both by 2 reasons; 1) the geometrical rough surface, which is derived from a macroporous structure presumably formed by spinodal decomposition, and 2) by the many organic groups and relatively few hydroxy groups exposed on the surface.  The contact angle of water droplet on any cut surface is above 150 °.

Surface Reactivity

Superamphiphobic Monolith
In vinyltrimethoxysilane (VTMS)-vinylmethyldimethoxysilane (VMDMS) co-precursor systems, marshmallow-like gels have rich vinyl groups on the surface. By using thiol-ene click reactions, these materials are easily functionalized. For instance, after a reaction with 1H,1H,2H,2H-perfluorodecanethiol, marshmallow-like gels achieve superoleophobicity. [3]

References

  1. Gen Hayase, Kazuyoshi Kanamori and Kazuki Nakanishi, “New flexible aerogels and xerogels derived from methyltrimethoxysilane/dimethyldimethoxysilane co-precursors”, J. Mater. Chem., 21, 17077-17079 (2011). doi: 10.1039/C1JM13664J
  2. Gen Hayase, Kazuyoshi Kanamori, Masashi Fukuchi, Hironori Kaji and Kazuki Nakanishi, “Facile Synthesis of Marshmallow-like Macroporous Gels Usable under Harsh Conditions for the Separation of Oil and Water”, Angew. Chem., Int. Ed., 52, 7, 1986-1989 (2013). doi:10.1002/anie.201207969
  3. Gen Hayase, Kazuyoshi Kanamori, George Hasegawa, Ayaka Maeno, Hironori Kaji and Kazuki Nakanishi, “A Superamphiphobic Macroporous Silicone Monolith with Marshmallow-like Flexibility”, Angew. Chem., Int. Ed., 52, 41, 10788–10791 (2013). doi:10.1002/anie.201304169