Elastomeric Light Emitting Polymer Enhanced by Interpenetrating Networks.
Conjugated polymers containing long-chain alkyl side groups for solubility are generally unstretchable: large strain induces crack formation, fracture, or plastic deformation. When the polymers are stretched to reorient the conjugated chains along the stretching direction, high dichroic ratio is observed both for absorption of the ground state and radiative decay of the excited state. Here an interpenetrating polymer network (IPN) approach is reported to impart elastomeric deformability to a conjugated polymer. A soluble alkyloxy phenyl substituted poly(1,4-phenylenevinylene) (SY-PPV) with bright yellow fluorescent emission was admixed with an ionically conductive medium containing poly(ethylene oxide), exoxylated trimethylolpropanetriacrylate, and lithium trifluoromethanesulfonate. The spin-cast blend film formed an IPN morphology wherein SY-PPV forms a porous network with pores filled by the ionic medium. PeakForce quantitative nanomechanical mapping showed that the local Young's modulus was high in the SY-PPV phase, while the ionic phase was two-times softer. No global polarization of the SY-PPV chains was observed at strains up to 100% as the dichroic ratio remains close to 1. Light-emitting devices based on the blend sandwiched between two stretchable transparent composite electrodes could be stretched by up to 140% strain. No electroluminescence polarization was observed.
Department of Materials Science and Engineering, Henry Samuli School of Engineering and Applied Science, University of California, Los Angeles , 420 Westwood Plaza, Los Angeles, California 90095, United States.
Huier
H
Gao
Department of Materials Science and Engineering, Henry Samuli School of Engineering and Applied Science, University of California, Los Angeles , 420 Westwood Plaza, Los Angeles, California 90095, United States.|College of Materials Science and Engineering, Zhejiang University of Technology , 18 Chaowang Road, Hangzhou 310014, China.
Si
S
Chen
Department of Materials Science and Engineering, Henry Samuli School of Engineering and Applied Science, University of California, Los Angeles , 420 Westwood Plaza, Los Angeles, California 90095, United States.
Jiajie
J
Liang
Department of Materials Science and Engineering, Henry Samuli School of Engineering and Applied Science, University of California, Los Angeles , 420 Westwood Plaza, Los Angeles, California 90095, United States.
Qibing
Q
Pei
elastomeric; interpenetrating networks; light emitting electrochemical cell; morphology; polymer blend; stretchable