Thermo-responsive self-folding strings for programmable matter

Whether metal, polymer or ceramic, crystalline or amorphous, both the nature and arrange-
ment of the elements constituting matter dictate its physical properties. Traditional processes
can be used to fabricate structures relying on processes such as additive manufacturing,
self-folding, and modular assembly. Compared to other approaches, self-folding structures
present the advantage of shape morphing to 3D using various actuators including smart
materials. Nevertheless, self-folding structures face challenges, including universality for
shape morphing, scale and folding torque, addressability and collisions, reversibility and
reprogrammability, remote actuation, sensors, communication, and computation. In this
thesis, three different approaches are presented, each related to distinct challenges. First, I
propose an environment with reduced gravity to lower the required folding torque, along
with a new design for a modular chain that allows the hinges of the string to be manually
reset to their initial state and the string to be reprogrammed in order to self-fold into a
different configuration. This was demonstrated by the self-folding of three different voxel
configurations used for crystalline structures. Second, I propose a manufacturing process
enabling the reversibility of self-folding to be turned off permanently. This was implemented
on semi-crystalline structures, including a a pyramid, a rectangle and a cube, and the re-
sults were extended to small robots whose locomotion could be tuned. Third, I propose a
design methodology to render self-folding hinges via magnetic induction to be addressed
sequentially by adapting the design of the magnetic receivers and their configurations. In
addition, a method was proposed to translate knots based on continuous deformations into
folding patterns with discontinuous deformations. These methodologies were tested on a
sequential self-folding box, a bio-inspired mimosa pudica leaf and an overhand knot to
replicate amorphous structures.