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220 Biomimetics: Biologically Inspired Technologies

7.4.3.1 Intrinsic Material

The unique arrangement of the constituent atoms of intrinsic materials would give rise to:

. unique potential field surface around them;
. unique charge distribution;
. unique internal energy gradients.
It is through these internal energy gradients that two particular intrinsic materials would interact
with each other. Hence the behavior of the intrinsic material would be a direct function of its
internal energy gradients.
7.4.3.2 Interaction Laws

The final objective of any interacting intrinsic materials would be to achieve the intrinsic balance of
the resulting system (termed self-balancing). This would translate to achieving minimum energy
gradients in all directions for all interacting materials. The final system would then be defined by its
new achieved internal energy gradients. These intrinsic energy gradients would also be influenced
by the external fields.

7.4.3.3 Self-Balancing

It implies that the materials considered would tend to align with its intrinsic energy gradients and
would try to minimize the formed unbalance. The classical instance of self-replication via energy-
minimized self-assembly was first demonstrated in the late 1950s. The canonical example of this
approach is called the Penrose Blocks (Penrose and Penrose, 1957; Penrose, 1958). The unbalance
and the property of self-balancing are similar in essence to what is postulated by the law of entropy.
This concept of self-balancing is motivated from the law of maximum entropy production accord-
ing to which a system follows a path which minimizes the potential or maximizes entropy at the
maximum rate (Archives of Science, 2001).

7.4.3.4 Growth and the Reproductive Limit

An intrinsic material would have a property of growth (an important variable for replication). This
property of growth only occurs when the system is provided with some energy maybe in the form of
additional intrinsic material or external gradients. Growth cannot happen in isolation. This implies
that in the process of self-balancing, it is possible that the particular configuration of the intrinsic
material is stable up to a particular level. This level would be governed by the strength of the
potential gradients for that intrinsic material and the extrinsic gradients. Therefore, the growth
implies that the intrinsic material can achieve higher state by not disturbing its self-balance or
increasing it further. But this growth can only be achieved to a particular extent; beyond it, it tends
to disintegrate by following the paths defined by the laws of maximum entropy production. And this
particular limit of growth is termed Reproductive Limit.

7.4.3.5 Self-Filtering and Self-Healing

The concept of replication further demands that the materials thus designed should exhibit the
property of self-filtering and self-healing. Self-filtering implies that the material involved in the
systems exhibiting self-replication will not allow any kind of growth pattern but only a particular
one. This particular growth pattern (which inherently depends on the interactions of the compon-