A tunable cohesive granular material
We offer a new technology to fabricate porous material with tunable elasticity and desired shapes and sizes. Using granules made of a stiff substance (glass) and mixing them with a small amount of an elastomeric substance (PDMS) leads to formation of the capillary bridges between the grains. The resulting mixture is cohesive and malleable, and can be poured into a mold of the desired shape. After the curing step, the solid capillary bridges between the granules are formed. The pores of this granular material can be adjusted by selecting the size and the shape of the granules. The elasticity can be easily tuned by varying the Young’s modulus of the solid capillary bridges. Fig. 1 shows the granular material formed of the glass beads and PDMS.
Our results show that the elastic modulus of the granular material prepared as described above can be adjusted from 1 kPa to 1.5 MPa, and that the material can be reversibly deformed for large maximal strains of about 8%. Permeability can also be finely adjusted by varying the grain sizes and polymer content. Typical measured permeability ranges from 10-12 m2 (low permeability) to 10-10 m2 (high permeability).
- Variable elasticity from 1 kPA to 1.5 MPa
- Adjustable pore size and permeability
- Tunable mechanical properties
- Curable in the desired shape
- Applicability as fluid filter and membrane
- Usage of inert materials
Hemmerle, A.; Schröter, M.; Goehring, L., "A tunable cohesive granular material", arXiv:1607.07360 (under review)
US patent application filed in July 2016.
- Ref.-Nr.: 0705-5158-BC (467,6 KiB)
Dr. Bernd Ctortecka, M. Phil.
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