MASTER THESIS Biomimetic potential of sponge ... - IAP/TU Wien

(iv)
(v)
crystallize the previously deposited mineral films
repeat steps (i)-(iv)
The resultant artificial nacre visually resembles its natural role model on all different
scales. Scanning electron micrographs (SEM, Figure 21e vs. f) reveal that the characteristic
tablet structure of aragonite in nacre is similarly maintained in the calcareous tablets of the
artificial nacre. With the naked eye a feature related to the same, small scale can be
detected: iridescence (change of colour with the viewing angle). This optical phenomenon
arises due to the regular periodicity of nacre (Figure 21c), and is quite similarly observed in
the artificial nacre plate (Figure 21b), confirming the good control over layer thickness in this
artificial organic-inorganic composite. Indentation of artificial and natural nacre revealed
that the toughness of both materials is similar, with differences due to the used crystal from
of CaCO 3 (cal org in artificial nacre vs. aragonite in biogenic nacre).
The approach reported in that publication importantly is quite similar to the
biomineralization of nacre in the living organism, e.g., abalone (Lin et al., 2008). Importantly,
the methods used during synthesis (e.g. dip-coating, etching with NaOH) should easily be upscaled.
This stands in contrast to many attempts to mimic the formation of sponge spicules,
since often biomolecules (like silicatein) are involved in proposed and experimented
pathways (Tahir et al., 2005) (Müller et al., 2009c) (André et al., 2011).
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