Intrinsic self-healing polymers with a high E -modulus based on dynamic reversible urea bonds

One of the hardest self-healing polymers ever reported has been prepared using the reversible bonds of sterically hindered urea groups. Polymers that can re-form internal chemical links after being scratched or cracked are usually subject to design constraints that lower their mechanical strength. To overcome these constraints, Martin D. Hager and colleagues from Friedrich Schiller University Jena, Germany, created a series of poly(methacrylate) polymers bearing reversible urea units. By simply exposing the starting reagents to brief flashes of light, they prepared a cross-linked polymer featuring the urea units on the poly(methacrylate) chains resulting in mechanically tough materials. After optimizing the cross-link density, the team deliberately scratched the polymer and then heated it to begin the self-healing process. Temperatures of about 100 degree Celsius were sufficient to open urea bonds up and initiate material repair.

[1]  J. Pople,et al.  Self‐Consistent Molecular‐Orbital Methods. IX. An Extended Gaussian‐Type Basis for Molecular‐Orbital Studies of Organic Molecules , 1971 .

[2]  J. Pople,et al.  Self—Consistent Molecular Orbital Methods. XII. Further Extensions of Gaussian—Type Basis Sets for Use in Molecular Orbital Studies of Organic Molecules , 1972 .

[3]  Parr,et al.  Development of the Colle-Salvetti correlation-energy formula into a functional of the electron density. , 1988, Physical review. B, Condensed matter.

[4]  A. Becke.  Density-functional thermochemistry. III. The role of exact exchange , 1993 .

[5]  N. Sottos,et al.  Autonomic healing of polymer composites , 2001, Nature.

[6]  J. Chang,et al.  A sol–gel reaction of vinyl polymers based on thermally reversible urea linkages , 2001 .

[7]  S. Nutt,et al.  A Thermally Re-mendable Cross-Linked Polymeric Material , 2002, Science.

[8]  Stuart J Rowan,et al.  Dynamic covalent chemistry. , 2002, Angewandte Chemie.

[9]  Ajit K. Mal,et al.  New Thermally Remendable Highly Cross-Linked Polymeric Materials , 2003 .

[10]  S. Zwaag.  Self‐Healing Materials , 2007 .

[11]  L. Radom,et al.  An evaluation of harmonic vibrational frequency scale factors. , 2007, The journal of physical chemistry. A.

[12]  P. Cordier,et al.  Self-healing and thermoreversible rubber from supramolecular assembly , 2008, Nature.

[13]  Giovanni Scalmani,et al.  Gaussian 09W, revision A. 02 , 2009 .

[14]  H. Otsuka,et al.  Dynamic covalent polymers: Reorganizable polymers with dynamic covalent bonds , 2009 .

[15]  Jonathan Seppala,et al.  A healable supramolecular polymer blend based on aromatic pi-pi stacking and hydrogen-bonding interactions. , 2010, Journal of the American Chemical Society.

[16]  Ludwik Leibler,et al.  Self‐Healing Supramolecular Networks , 2010 .

[17]  Justin R. Kumpfer,et al.  Optically healable supramolecular polymers , 2011, Nature.

[18]  L. Ye,et al.  Self-healing biodegradable poly(urea-urethane) elastomers based on hydrogen bonding interactions , 2013, Chinese Journal of Polymer Science.

[19]  R. Hoogenboom.  Hard autonomous self-healing supramolecular materials--a contradiction in terms? , 2012, Angewandte Chemie.

[20]  Christopher Barner-Kowollik,et al.  Current trends in the field of self-healing materials , 2012 .

[21]  Aaron M Kushner,et al.  Multiphase design of autonomic self-healing thermoplastic elastomers. , 2012, Nature chemistry.

[22]  Jürgen Popp,et al.  Self‐Healing Polymer Coatings Based on Crosslinked Metallosupramolecular Copolymers , 2013, Advanced materials.

[23]  J. Pascault,et al.  On the versatility of urethane/urea bonds: reversibility, blocked isocyanate, and non-isocyanate polyurethane. , 2013, Chemical reviews.

[24]  S. Gräfe,et al.  Self-healing mechanism of metallopolymers investigated by QM/MM simulations and Raman spectroscopy. , 2014, Physical chemistry chemical physics : PCCP.

[25]  Filip Du Prez,et al.  One-Pot Thermo-Remendable Shape Memory Polyurethanes , 2014 .

[26]  Germán Cabañero,et al.  Catalyst-free room-temperature self-healing elastomers based on aromatic disulfide metathesis , 2014 .

[27]  Jianjun Cheng,et al.  Hydrolyzable Polyureas Bearing Hindered Urea Bonds , 2014, Journal of the American Chemical Society.

[28]  H. Grande,et al.  The processability of a poly(urea-urethane) elastomer reversibly crosslinked with aromatic disulfide bridges , 2014 .

[29]  E. J. Foster,et al.  Reinforcement of Optically Healable Supramolecular Polymers with Cellulose Nanocrystals , 2014 .

[30]  Santiago J. Garcia,et al.  Effect of polymer architecture on the intrinsic self-healing character of polymers , 2014 .

[31]  Jianjun Cheng,et al.  Dynamic urea bond for the design of reversible and self-healing polymers , 2014, Nature Communications.

[32]  M. Mackay,et al.  Multivalency in healable supramolecular polymers: the effect of supramolecular cross-link density on the mechanical properties and healing of non-covalent polymer networks , 2014 .

[33]  S. Zwaag,et al.  Characterization of Self-Healing Polymers: From Macroscopic Healing Tests to the Molecular Mechanism , 2015 .

[34]  S. van der Zwaag,et al.  Connecting supramolecular bond lifetime and network mobility for scratch healing in poly(butyl acrylate) ionomers containing sodium, zinc and cobalt. , 2015, Physical chemistry chemical physics : PCCP.

[35]  U. Schubert,et al.  Shape memory polymers: Past, present and future developments , 2015 .

[36]  H. Terryn,et al.  A shape-recovery polymer coating for the corrosion protection of metallic surfaces. , 2015, ACS applied materials & interfaces.

[37]  S. Zwaag,et al.  Correlation between scratch healing and rheological behavior for terpyridine complex based metallopolymers , 2015 .

[38]  B Dietzek,et al.  Two-dimensional Raman correlation spectroscopy reveals molecular structural changes during temperature-induced self-healing in polymers based on the Diels-Alder reaction. , 2015, Physical chemistry chemical physics : PCCP.

[39]  Ulrich S. Schubert,et al.  Self-Healing Polymers Based on Reversible Covalent Bonds , 2015 .

[40]  Atsushi Takahara,et al.  Self-Healing of a Cross-Linked Polymer with Dynamic Covalent Linkages at Mild Temperature and Evaluation at Macroscopic and Molecular Levels , 2015 .

[41]  L. Leibler,et al.  Vinylogous Urethane Vitrimers , 2015 .

[42]  Qiuyu Zhang,et al.  Rapid and efficient synthesis of isocyanate microcapsules via thiol-ene photopolymerization in Pickering emulsion and its application in self-healing coating , 2016 .

[43]  Jie Yin,et al.  Environmental friendly polymers based on schiff-base reaction with self-healing, remolding and degradable ability , 2016 .

[44]  Ke Yang,et al.  Malleable and Recyclable Poly(urea‐urethane) Thermosets bearing Hindered Urea Bonds , 2016, Advanced materials.

[45]  Emily A. Hoff,et al.  RAFT Polymerization of “Splitters” and “Cryptos”: Exploiting Azole-N-carboxamides As Blocked Isocyanates for Ambient Temperature Postpolymerization Modification , 2016 .

[46]  Y. Takashima,et al.  Self-Healing Materials Formed by Cross-Linked Polyrotaxanes with Reversible Bonds , 2016 .

[47]  Chunmei Li,et al.  Synthesis of Cyanate Ester Microcapsules via Solvent Evaporation Technique and Its Application in Epoxy Resins as a Healing Agent , 2016 .

[48]  R. Geitner,et al.  Polymeric Halogen-Bond-Based Donor Systems Showing Self-Healing Behavior in Thin Films. , 2017, Angewandte Chemie.