Properties

Mechamical Properties

Marshmallow gel is flexible in compression and bending and recovers its shape immediately after unloading. This flexibility comes from flexible polymers and micrometer-scale structures. [1] It exhibits some flexibility even in liquid nitrogen (below the glass transition point). [2]

Cold resistance/Heat insulation

The mechanical properties of MTMS–DMDMS marshmallow-like gels hardly change from −130 to 320 °C. They have a low thermal conductivity of about 30 mW m−1K−1. By packing marshmallow-like gels in a thermos bottle and soaking with liquid nitrogen, it can be used as a simple transport container for frozen embryos. [3]

DIY dry shipper using marshmallow-like gel

Superhydrophobicity

Marshmallow-like gels have hydrophobicity.[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°.

Since the marshmallow-like gel of standard composition is hydrophobic and lipophilic, it can absorb and separate only oil from water like a sponge.

Giant vesicle (liposome) formation

By absorbing and squeezing out buffer from a phospholipids-coated marshmallow-like gel, giant vesicle (liposome) dispersion can be prepared easily and in a large scale. [4]

Schematic image of giant vesicle generation using marshmallow-like gel

Surface Reactivity

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,2Hperfluorodecanethiol, marshmallow-like gels achieve superoleophobicity. [5]

Surface-treated marshmallow gel will repel various organic liquids such as hexadecane.

Superamphiphobic marshmallow-like gel

References

  1. Gen Hayase, Kazuyoshi Kanamori and Kazuki Nakanishi, “New flexible aerogels and xerogels derived from methyltrimethoxysilane/dimethyldimethoxysilane co-precursors”, J. Mater. Chem. 2011, 21, 17077-17079. 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. 2013, 52, (7), 1986-1989. doi:10.1002/anie.201207969
  3. Gen Hayase, Yasutaka Ohya, “Marshmallow-like silicone gels as flexible thermal insulators and liquid nitrogen retention materials and their application in containers for cryopreserved embryos”, Appl. Mater. Today 2017, 9, 560-565. doi:10.1016/j.apmt.2017.10.004
  4. Gen Hayase, Shin-ichiro M. Nomura, “Large-Scale Preparation of Giant Vesicles by Squeezing a Lipid-Coated Marshmallow-Like Silicone Gel in a Buffer”, Langmuir 2018, 34, (37), 11021-11026. doi:10.1021/acs.langmuir.8b01801
  5. 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. 2013, 52, (41), 10788–10791. doi:10.1002/anie.201304169