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Actuating hydrogel films  (self-folding films)

Dr. Leonid Ionov
Svetlana Zakharchenko
Georgi Stoychev
Vladislav Stroganov
Evgeni Sperling

We are interested in engineering of functional polymer thin films which are able to reversibly fold and form different 3D objects in response to change of environmental conditions. The primary goal is to use self-rolled tubes and self-folding capsules for encapsulation of cells. PDF presentation about self-folding thin films can be downloaded here.

Self-folding films are polymer bilayers. First layer is crosslinked water swellable polymer - hydrogel. This is thermoresponsive poly(N-isopropylacrylamide) (PNIPAM) hydrogel. Second layer is hydrophobic polymer, for example, polycaprolactone. PNIPAM hydrogel layer swells in water below 30°C that increases stress in the film and leads to rolling. Heating above 30°C shrinks the hydrogel layer and leads to unrolling.

On focus is to use thermo-magneto-sensitive self-rolled tubes for controlled encapsulation and release of microparticles, cells and drugs. We investigate reversible rolling and unrolling of the polymer films, reversible capture and release of microparticles in response to change of temperature as well as manipulation of particle-loaded microtubes using external magnetic field. Now the approach for desing of fully biodegradable self-rolled tubes is developed. The suggested approach is promising for controlled delivery of drugs and cells in living organisms as well as to design scaffolds for tissue engineering.


Scheme of capture and release of microparticles by self-rolled microtubes. The poly(N-isopropylacrylamide) (PNIPAM)- polycaprolactone (PCL) bilayer is able to form  tubes and to encapsulate microparticles due to swelling of the thermoresponsive PNIPAM hydrogel layer at reduced temperature (b). The particle can be released at elevated temperature when the tubes are unrolled (c).


Stroganov, V.; Zakharchenko, S.; Sperling, E.; Meyer, A.K.; Schmidt, O.G; Ionov, L
Biodegradable self-folding polymer films with controlled thermo-triggered folding
Advanced Functional Materials, 2014 accepted.

Magdanz, V.; Stoychey, G.; Ionov, L.; Sanchez, S.; Schmidt, O.
Stimuli-Responsive Microjets with Reconfigurable Shape more
Angew. Chem. Int. Ed., 126 (10), 2014, 271-2715.

Ionov, L. 
Polymer origami: programming the folding with shape more
e-Polymers 14(2), 2014, 109-114.

Synytska, A.; Ionov, L.
Stimuli-Responsive Janus particles more
Particle & Particle Systems Characterization 30, 2013, 922-930.

Ionov, L.
Biomimetic hydrogel-based actuating systems more
Advanced Functional Materials 23, 2013, 4555–4570.

Zakharchenko, S.; Puretskiy, N.; Stoychev, G.; Waurisch, C.; Hickey, S.G.; Eychmüller, A.; Sommer, J.U.; Ionov, L.
Stimuli-responsive hierarchically self-assembled 3D porous polymer-based structures with aligned pores  more
Journal of Materials Chemistry B (1) 2013, 1786-1793.

Ionov, L.; Zakharchenko, S.; Stoychev, G.
Soft Microorigami: Stimuli-responsive Self-folding Polymer Films  more
Advances in Science and Technology (77) 2013, 348-353.

Ionov, L.
3D Microfabrication using stimuli-responsive self-folding polymer films  more
Polymer Reviews (53) 2013, 92-107 .

Stoychev, G.; Turcaud, S.; Dunlop, J.; Ionov, L.
Hierarchical multi-step folding of polymer bilayers more
Advanced Functional Materials (23) 2013, 2295.

Ionov, L.
Bioinspired microorigami by self-folding polymer films more
Macromolecular Chemistry and Physics, accepted.

Stoychev, G.; Zakharchenko, S.; Turcaud, S.; Dunlop, J.; Ionov, L.
Shape programmed folding of stimuli-responsive polymer bilayers more
ACS Nano 6 (5) (2012), 3925–3934.

Ionov, L.;
Biomimetic 3D self-assembling biomicroconstructs by spontaneous deformation of thin polymer films more
Journal of Materials Chemistry (2012), 22, 19366–19375.

Luchnikov, V.; Ionov, L.; Stamm, M.
Self-rolled polymer tubes: novel tools for microfluidics, microbiology and drug-delivery systems more
Macromolecular Rapid Communications 32(24) (2011) 1943–1952.

Ionov, L.
Soft microorigami: self-folding polymer films more
Soft Matter 7 (2011) 6786–6791.  

Zakharchenko, S.; Sperling, E.; Ionov, L.
Fully biodegradable self-rolled polymer tubes: a candidate for tissue engineering scaffolds more
Biomacromolecules 12 (6) (2011)  2211–2215.

Stoychev, G.; Puretskiy, N.;  Ionov, L.
Self-folding all-polymer thermoresponsive microcapsules more
Soft Matter 7 (2011) 3277-3279

Zakharchenko, S.; Puretskiy, N.; Stoychev, G.; Stamm, M.; Ionov, L.
Temperature controlled encapsulation and release using partially biodegradable thermo-magneto-sensitive self-rolling tubes more
Soft Matter 6 (2010) 2633-2636

Actuating hydrogel films  (self-folding films)
Actuating hydrogel films  (self-folding films)


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Dr. Leonid Ionov