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Control Viscoelasticity of Polymer Networks with Crosslinks of Superposed Fast and Slow Dynamics
Author(s) -
Chen Hao,
Zhang Jin,
Yu Wenting,
Cao Yi,
Cao Zhaozhen,
Tan Yebang
Publication year - 2021
Publication title -
angewandte chemie international edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 1433-7851
DOI - 10.1002/anie.202105112
Subject(s) - viscoelasticity , polymer , materials science , molecular dynamics , rheology , chemical physics , protonation , relaxation (psychology) , stiffness , nanotechnology , computational chemistry , chemistry , composite material , organic chemistry , ion , social psychology , psychology
Depending on the dynamics of the crosslinks, polymer networks can have distinct bulk mechanical behaviors, from viscous liquids to tough solids. Here, by means of designing a crosslink with variable molecular dynamics, we show the control of viscoelasticity of polymer networks in a broad range quantitatively. The hexanoate‐isoquinoline@cucurbit[7]uril (HIQ@CB[7]) crosslink exhibits in a combination of protonated and deprotonated states of similar association affinity but distinct molecular dynamics. The molecular property of this crosslink is contributed by linear combination of the parameters at the two states, which is precisely tuned by pH. Using this crosslink, we achieve the quantitative control of viscoelasticity of quasi‐ideal networks in 5 orders of magnitude, and we show the reversible control of mechanical response, such as stiffness, strength and extensibility, of tough random polymer networks. This strategy offers a way to tailor the mechanical properties of polymer networks at the molecular level and paves the way for engineering “smart” responsive materials.