UV light induced plasticization and light activated shape memory of spiropyran doped ethylene-vinyl acetate copolymers.

Light activated shape memory polymers (LASMPs) are relatively new kinds of smart materials and have significant technological applications ranging from biomedical devices to aerospace technology. EVA films doped with spiropyran with contents ranging from 0.1% to 3% show efficient UV activated shape memory behaviors if the fixed shape deformation is limited within 80%. For EVA films containing 3% spiropyran, UV irradiation causes a decrease in EVA modulus of about 44%. FT-IR and solid (13)C NMR in association with UV-vis absorption analysis demonstrate that UV irradiation transforms spiropyran from the SP form to the MC form, meanwhile, it induces an increase in the molecular mobility in the amorphous phase of EVA. Thus, the spiropyran-doped EVA films act as LASMPs via a mechanism of light induced plasticization. Light activated spiropyran acts as a plasticizer to EVA.

[1]  L. Yahia,et al.  Medical applications of shape memory polymers , 2007, Biomedical materials.

[2]  Bin Li,et al.  Light‐Driven Side‐On Nematic Elastomer Actuators , 2003 .

[3]  Andrew M. Baker,et al.  An X-ray diffraction and modelling study of short chain branch location within the structure of polyethylene , 2001 .

[4]  Qing-Qing Zhou,et al.  Crown ethers with spiropyran units incorporated in the ring frameworks for pH-triggered ion recognition at the air–water interface , 2014 .

[5]  Feng-kui Li,et al.  Shape memory effect of ethylene–vinyl acetate copolymers , 1999 .

[6]  H. Meng,et al.  A review of stimuli-responsive shape memory polymer composites , 2013 .

[7]  Costas Fotakis,et al.  All‐Optical Reversible Actuation of Photochromic‐Polymer Microsystems , 2005 .

[8]  R. Langer,et al.  Light-induced shape-memory polymers , 2005, Nature.

[9]  Martin L. Dunn,et al.  Photomechanics of light-activated polymers , 2009 .

[10]  J. Rogers,et al.  Deformable, Programmable, and Shape‐Memorizing Micro‐Optics , 2013 .

[11]  Christopher N. Bowman,et al.  Actuation in Crosslinked Polymers via Photoinduced Stress Relaxation , 2006 .

[12]  A. Lendlein,et al.  Multifunctional Shape‐Memory Polymers , 2010, Advanced materials.

[13]  Patrick T. Mather,et al.  Review of progress in shape-memory polymers , 2007 .

[14]  H. Meng,et al.  Reversible switching transitions of stimuli-responsive shape changing polymers , 2013 .

[15]  P. H. Daniels.  A brief overview of theories of PVC plasticization and methods used to evaluate PVC‐plasticizer interaction , 2009 .

[16]  Martin L. Dunn,et al.  Mechanisms of triple-shape polymeric composites due to dual thermal transitions , 2013 .

[17]  H. Oonishi,et al.  Characterization of ultrahigh molecular weight polyethylene irradiated with γ‐rays and electron beams to high doses , 1999 .

[18]  V. Ashby,et al.  Photoresponsive Polyesters for Tailorable Shape Memory Biomaterials , 2013 .

[19]  C. Bowman,et al.  Photoinduced Plasticity in Cross-Linked Polymers , 2005, Science.

[20]  Toshiyuki Tanaka,et al.  Reversible photo-switching interaction between spiropyrans and polymer pyridine residues in a solid polymer membrane , 2006 .

[21]  H. Kaji,et al.  Solid-State13C NMR Analyses for the Structure and Molecular Motion in theαRelaxation Temperature Region for Metallocene-Catalyzed Linear Low-Density Polyethylene , 2000 .

[22]  Xiang-Jie Gao,et al.  A General Approach Towards Thermoplastic Multishape‐Memory Polymers via Sequence Structure Design , 2013, Advanced materials.

[23]  B. Qu,et al.  Photoinitiated crosslinking of ethylene-vinyl acetate copolymers and characterization of related properties , 2007 .

[24]  M. Cristea,et al.  A new insight in the dynamo-mechanical behavior of poly(ethylene terephthalate) , 2010 .

[25]  R. Vaia,et al.  Light-activated shape memory of glassy, azobenzene liquid crystalline polymer networks , 2011 .

[26]  K. Agroui,et al.  Characterisation of EVA encapsulant material by thermally stimulated current technique , 2003 .

[27]  D. Vanderhart,et al.  Observations in Solid Polyethylenes by Carbon-13 Nuclear Magnetic Resonance with Magic Angle Sample Spinning , 1979 .

[28]  Yue Zhao,et al.  Light-triggered self-healing and shape-memory polymers. , 2013, Chemical Society reviews.

[29]  A. C. Barone,et al.  Photoinduced variable stiffness of spiropyran-based composites , 2011 .

[30]  T. Ikeda,et al.  Photomechanics: Directed bending of a polymer film by light , 2003, Nature.

[31]  M. Dunn,et al.  Photo-origami—Bending and folding polymers with light , 2012 .

[32]  Jinsong Leng,et al.  Infrared light‐active shape memory polymer filled with nanocarbon particles , 2009 .

[33]  A. Athanassiou,et al.  Photocontrolled mechanical phenomena in photochromic doped polymeric systems , 2003 .