Malleable and Self-Healing Covalent Polymer Networks through Tunable Dynamic Boronic Ester Bonds.

Despite numerous strategies involving dynamic covalent bond exchange for dynamic and self-healing materials, it remains a challenge to be able to tune the malleability and self-healing properties of bulk materials through simple small molecule perturbations. Here we describe the use of tunable rates of boronic ester transesterification to tune the malleability and self-healing efficiencies of bulk materials. Specifically, we used two telechelic diboronic ester small molecules with variable transesterification kinetics to dynamically cross-link 1,2-diol-containing polymer backbones. The sample cross-linked with fast-exchanging diboronic ester showed enhanced malleability and accelerated healing compared to the slow-exchanging variant under the same conditions. Our report demonstrates the possibility of transferring small molecule kinetics to dynamic properties of bulk solid material and may serve as a guide for the rational design of tunable dynamic materials.

[1]  S. Rowan,et al.  Understanding the mechanism of gelation and stimuli-responsive nature of a class of metallo-supramolecular gels. , 2006, Journal of the American Chemical Society.

[2]  Wei Zhang,et al.  Heat‐ or Water‐Driven Malleability in a Highly Recyclable Covalent Network Polymer , 2014, Advanced materials.

[3]  G. Wulff,et al.  Rapid Proton Transfer as Cause of an Unusually Large Neighboring Group Effect , 1984 .

[4]  B. Sumerlin,et al.  Dynamic-covalent macromolecular stars with boronic ester linkages. , 2011, Journal of the American Chemical Society.

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

[6]  Mark D. Smith,et al.  Self-repairing polymers: poly(dioxaborolane)s containing trigonal planar boron. , 2005, Chemical communications.

[7]  V. Lynch,et al.  A structural investigation of the N-B interaction in an o-(N,N-dialkylaminomethyl)arylboronate system. , 2006, Journal of the American Chemical Society.

[8]  M. Urban,et al.  Self-Repairing Oxetane-Substituted Chitosan Polyurethane Networks , 2009, Science.

[9]  Yoshifumi Amamoto,et al.  Self-healing of chemical gels cross-linked by diarylbibenzofuranone-based trigger-free dynamic covalent bonds at room temperature. , 2012, Angewandte Chemie.

[10]  S. Rowan,et al.  Using the dynamic bond to access macroscopically responsive structurally dynamic polymers. , 2011, Nature materials.

[11]  Krzysztof Matyjaszewski,et al.  Self‐Healing of Covalently Cross‐Linked Polymers by Reshuffling Thiuram Disulfide Moieties in Air under Visible Light , 2012, Advanced materials.

[12]  Jessica J. Cash,et al.  Room-Temperature Self-Healing Polymers Based on Dynamic-Covalent Boronic Esters , 2015 .

[13]  Jincui Gu,et al.  Self-healable macro-/microscopic shape memory hydrogels based on supramolecular interactions. , 2014, Chemical communications.

[14]  K. Abboud,et al.  Boronic Acid-Based Hydrogels Undergo Self-Healing at Neutral and Acidic pH. , 2015, ACS macro letters.

[15]  C. Hutton,et al.  Factors affecting the efficiency and stereoselectivity of α-amino acid synthesis by the Petasis reaction , 2006 .

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

[17]  S. Franzen,et al.  Study of the Mechanism of Electron-Transfer Quenching by Boron−Nitrogen Adducts in Fluorescent Sensors , 2003 .

[18]  T. Sager,et al.  Boronic acid based peptidic receptors for pattern-based saccharide sensing in neutral aqueous media, an application in real-life samples. , 2007, Journal of the American Chemical Society.

[19]  Brian J. Adzima,et al.  Covalent Adaptable Networks (CANs): A Unique Paradigm in Crosslinked Polymers. , 2010, Macromolecules.

[20]  F. Jäkle.  Advances in the synthesis of organoborane polymers for optical, electronic, and sensory applications. , 2010, Chemical reviews.

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

[22]  Ludwik Leibler,et al.  Silica-Like Malleable Materials from Permanent Organic Networks , 2011, Science.

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

[24]  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.

[25]  J. Lehn,et al.  Tunable fluorene-based dynamers through constitutional dynamic chemistry. , 2006, Chemistry.

[26]  Byron E. Collins,et al.  On the rate of boronate ester formation in ortho-aminomethyl-functionalised phenyl boronic acids , 2013, Supramolecular chemistry.

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

[28]  W. Murphy,et al.  Protein‐Based Hydrogels with Tunable Dynamic Responses , 2008 .

[29]  S. Irle,et al.  An n-channel two-dimensional covalent organic framework. , 2011, Journal of the American Chemical Society.

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

[31]  D. Hall.  Boronic acids : preparation and applications in organic synthesis, medicine and materials , 2011 .

[32]  S. Craig,et al.  Small-molecule dynamics and mechanisms underlying the macroscopic mechanical properties of coordinatively cross-linked polymer networks. , 2005, Journal of the American Chemical Society.

[33]  Yiseul Park,et al.  Significance of hydrophilic characters of organic dyes in visible-light hydrogen generation based on TiO2. , 2010, Organic letters.

[34]  S. Shinkai,et al.  Saccharide Sensing with Molecular Receptors Based on Boronic Acid , 1996 .

[35]  S. Craig,et al.  Strong means slow: dynamic contributions to the bulk mechanical properties of supramolecular networks. , 2005, Angewandte Chemie.

[36]  Olivia R. Cromwell,et al.  Self-healing multiphase polymers via dynamic metal-ligand interactions. , 2014, Journal of the American Chemical Society.

[37]  S. Shinkai,et al.  Boronic acids in molecular self-assembly. , 2008, Chemistry, an Asian journal.

[38]  Bielawski,et al.  Highly Efficient Ring-Opening Metathesis Polymerization (ROMP) Using New Ruthenium Catalysts Containing N-Heterocyclic Carbene Ligands C.B. is grateful to the National Science Foundation for a pre-doctoral fellowship. The authors thank Dr. Matthias Scholl for providing catalysts 4 a and 4 c. , 2000, Angewandte Chemie.