Light-induced formation of dynamic and permanent surface topologies in chiral-nematic polymer networks

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Abstract

We report a procedure and a material to make patterned surface topologies by light, both in a dynamic way where the structures disappear after exposure or such that the deformations remain permanently. The method is based on a photosensitized cross-linked liquid crystal network with chiral–nematic molecular order. The polymer network is made photoresponsive by a small concentration of copolymerized azobenzene monomers. Upon exposure with patterned UV light, the molecular order parameter in the network is decreased by the trans-to-cis isomerization of the azobenzene, resulting in a density decrease and corresponding local volume increase. Under normal conditions, the polymer network behaves fully elastic and the surface deformation is fast and reversible. To induce permanent deformation, the polymer network needs to be adjusted by chain transfer agents to control the kinetic chain length of the network main chains and allow out of the plane reorientation of the azobenzene moieties and a corresponding loss of molecular order.
Original languageEnglish
Pages (from-to)8005-8012
Number of pages8
JournalMacromolecules
Volume45
Issue number19
DOIs
Publication statusPublished - 2012

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Azobenzene
Polymers
Topology
Liquid Crystals
Isomerization
Chain length
Ultraviolet radiation
Liquid crystals
Monomers
Kinetics
azobenzene

Cite this

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title = "Light-induced formation of dynamic and permanent surface topologies in chiral-nematic polymer networks",
abstract = "We report a procedure and a material to make patterned surface topologies by light, both in a dynamic way where the structures disappear after exposure or such that the deformations remain permanently. The method is based on a photosensitized cross-linked liquid crystal network with chiral–nematic molecular order. The polymer network is made photoresponsive by a small concentration of copolymerized azobenzene monomers. Upon exposure with patterned UV light, the molecular order parameter in the network is decreased by the trans-to-cis isomerization of the azobenzene, resulting in a density decrease and corresponding local volume increase. Under normal conditions, the polymer network behaves fully elastic and the surface deformation is fast and reversible. To induce permanent deformation, the polymer network needs to be adjusted by chain transfer agents to control the kinetic chain length of the network main chains and allow out of the plane reorientation of the azobenzene moieties and a corresponding loss of molecular order.",
author = "D. Liu and C.W.M. Bastiaansen and {Toonder, den}, J.M.J. and D.J. Broer",
year = "2012",
doi = "10.1021/ma301628h",
language = "English",
volume = "45",
pages = "8005--8012",
journal = "Macromolecules",
issn = "0024-9297",
publisher = "American Chemical Society",
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Light-induced formation of dynamic and permanent surface topologies in chiral-nematic polymer networks. / Liu, D.; Bastiaansen, C.W.M.; Toonder, den, J.M.J.; Broer, D.J.

In: Macromolecules, Vol. 45, No. 19, 2012, p. 8005-8012.

Research output: Contribution to journalArticleAcademicpeer-review

TY - JOUR

T1 - Light-induced formation of dynamic and permanent surface topologies in chiral-nematic polymer networks

AU - Liu, D.

AU - Bastiaansen, C.W.M.

AU - Toonder, den, J.M.J.

AU - Broer, D.J.

PY - 2012

Y1 - 2012

N2 - We report a procedure and a material to make patterned surface topologies by light, both in a dynamic way where the structures disappear after exposure or such that the deformations remain permanently. The method is based on a photosensitized cross-linked liquid crystal network with chiral–nematic molecular order. The polymer network is made photoresponsive by a small concentration of copolymerized azobenzene monomers. Upon exposure with patterned UV light, the molecular order parameter in the network is decreased by the trans-to-cis isomerization of the azobenzene, resulting in a density decrease and corresponding local volume increase. Under normal conditions, the polymer network behaves fully elastic and the surface deformation is fast and reversible. To induce permanent deformation, the polymer network needs to be adjusted by chain transfer agents to control the kinetic chain length of the network main chains and allow out of the plane reorientation of the azobenzene moieties and a corresponding loss of molecular order.

AB - We report a procedure and a material to make patterned surface topologies by light, both in a dynamic way where the structures disappear after exposure or such that the deformations remain permanently. The method is based on a photosensitized cross-linked liquid crystal network with chiral–nematic molecular order. The polymer network is made photoresponsive by a small concentration of copolymerized azobenzene monomers. Upon exposure with patterned UV light, the molecular order parameter in the network is decreased by the trans-to-cis isomerization of the azobenzene, resulting in a density decrease and corresponding local volume increase. Under normal conditions, the polymer network behaves fully elastic and the surface deformation is fast and reversible. To induce permanent deformation, the polymer network needs to be adjusted by chain transfer agents to control the kinetic chain length of the network main chains and allow out of the plane reorientation of the azobenzene moieties and a corresponding loss of molecular order.

U2 - 10.1021/ma301628h

DO - 10.1021/ma301628h

M3 - Article

VL - 45

SP - 8005

EP - 8012

JO - Macromolecules

JF - Macromolecules

SN - 0024-9297

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