Conformational Entropy as a Means to Control the Behavior of Poly(diketoenamine) Vitrimers In and Out of Equilibrium

Journal Article · 21 November 2019 · Angewandte Chemie

DOI: https://doi.org/10.1002/ange.201912223 · OSTI ID:1575100

He, Changfei ^[1]; Christensen, Peter R. ^[2]; Seguin, Trevor J. ^[3]; Dailing, Eric A. ^[2]; Wood, Brandon M. ^[4]; Walde, Rebecca K. ^[2]; Persson, Kristin A. ^[5]; Russell, Thomas P. ^[6]; Helms, Brett A.  ^[7]

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1. Beijing Advanced Innovation Center, for Soft Matter Science and Engineering Beijing University, of Chemical Technology Beijing 100029 China
2. The Molecular Foundry Lawrence Berkeley National Laboratory 1 Cyclotron Road Berkeley CA 94720 USA
3. Energy Technologies Area Lawrence Berkeley National Laboratory 1 Cyclotron Road Berkeley CA 94720 USA
4. Graduate Group of Applied Science and Technology University of California Berkeley CA 94720 USA, Environmental Energy Technologies Division Lawrence Berkeley National Laboratory 1 Cyclotron Road Berkeley CA 94720 USA
5. Materials Science and Engineering Department University of California Berkeley CA 94720 USA
6. Beijing Advanced Innovation Center, for Soft Matter Science and Engineering Beijing University, of Chemical Technology Beijing 100029 China, Materials Sciences Division Lawrence Berkeley National Laboratory 1 Cyclotron Road Berkeley CA 94720 USA, Polymer Science and Engineering Department University of Massachusetts Amherst MA 01003 USA
7. The Molecular Foundry Lawrence Berkeley National Laboratory 1 Cyclotron Road Berkeley CA 94720 USA, Materials Sciences Division Lawrence Berkeley National Laboratory 1 Cyclotron Road Berkeley CA 94720 USA

Abstract Control of equilibrium and non‐equilibrium thermomechanical behavior of poly(diketoenamine) vitrimers is shown by incorporating linear polymer segments varying in molecular weight (MW) and conformational degrees of freedom into the dynamic covalent network. While increasing MW of linear segments yields a lower storage modulus at the rubbery plateau after softening above the glass transition (T _g ), both T _g and the characteristic time of stress relaxation are independently governed by the conformational entropy of the embodied linear segments. Activation energies for bond exchange in the solid state are lower for networks incorporating flexible chains; the network topology freezing temperature decreases with increasing MW of flexible linear segments but increases with increasing MW of stiff segments. Vitrimer reconfigurability is therefore influenced not only by the energetics of bond exchange for a given network density, but also the entropy of polymer chains within the network.

• Sponsoring Organization: USDOE
• OSTI ID: 1575100
• Journal Information: Angewandte Chemie, Journal Name: Angewandte Chemie Vol. 132 Journal Issue: 2; ISSN 0044-8249
• Publisher: Wiley Blackwell (John Wiley & Sons)Copyright Statement
• Country of Publication: Germany
• Language: English