1. MATERIALS SCIENCE
& ENGINEERING
DEPARTMENT
OF
Self-Folding of Polymer Sheets Along Discontinuous Hinges
Mishal PB, Ying Liu, Jan Genzer, Michael D. Dickey
Department of Chemical and Biomolecular Engineering, North Carolina State University
Supported by a REM Supplement to an EFRI Grant from the National Science Foundation
Quality and accuracy of a fold from thermal readingsIntroduction
How positioning affects folding timesApplications of Self-folding
Ongoing ResearchLight absorption and experimental setup
Conclusions
Positioning of features is more influential than ink ratio
When warping occurs at critical point, time can
increase significantly
Self-folding using localized light
absorption
Liu & al., Soft Matter. (2012)
Hypotheses
The positioning of features is as important as the
amount of ink on a hinge regarding folding times.
Folding will be better and more accurate when
temperature on the hinge is relatively high.
4 discontinuous hinge patterns
Polymer exposed to light
Using the polymer polystyrene
Liu & al., Soft Matter. (2012)
Observations
Warping folds may stretch
area between features
causes cratering of polymer
Features on hinges tend to
stretch in one direction and
shrink in the other
Ink is printed on
polymer at desired
hinge
Hot plate heats
bottom of polymer,
usually at 90C
Hinge may be
deformed,
bent, or folded
The Dickey & Genzer Research Groups
Complex origami through Self-folding
Self-unfolding of satellite using sunlight
Credit: Harvard’s Wyss Institution
Self-folding and unfolding robots
ChangKyu Yoon et al 2014 Smart
Mater.
Self-folding grippers for biomedical
purposes (scale bars: 550, 650, 400 nm)
ChangKyu Yoon et al 2014 Smart
Mater.
Self-folding cubic
capsules to hold
medicines and other
cargo (scale bar: 350 nm)
Liu & al., Soft Matter. (2012)
)
Credit: Brigham State University, NSF
Folding occurs faster when features are
closer together
More interaction
than
Near Perfect Fold Warping
Points of
interest
Created in COMSOL Multiphysics Modeling
Software
Conclusion
It is possible to predict the way a
polymer will fold by the
temperature between the features
Temperatures at the
points of interest were
measured
Theoretical folding “zones” were
observed on the way the polymers folds,
divided by critical temperatures
Correlating thermal
modeling to folding behavior
observed experimentally
Polymer samples simulating heat transfer in
COMSOL Multiphysics modeling software
Understanding the
conditions that cause
cratering
Likely to occur when
temperature at point
1 increases much
faster than at point 2
1
2
1 2
Understanding the
shrinkage of features
occurring due to heat
flow between them
Studying the effects of heat loss to
environmental factors, such as
convective heat loss due to air flow and
conductive heat loss to the hot plate
included in the experimental setup