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Low-Temperature Meltable Elastomers Based on Linear Polydimethylsiloxane Chains Alpha, Omega-Terminated with Mesogenic Groups as Physical Crosslinkers: A Passive Smart Material with Potential as Viscoelastic Coupling. Part I: Synthesis and Phase Behavior

1
Institute of Macromolecular Chemistry, Czech Academy of Sciences, Heyrovskeho nam. 2, CZ-162 06 Praha, Czech Republic
2
Faculty of Science, Charles University, Albertov 6, CZ-128 00 Praha 2, Czech Republic
3
Faculty of Chemistry, Rzeszow University of Technology, al. Powstancow Warszawy 6, PL-35-959 Rzeszow, Poland
*
Author to whom correspondence should be addressed.
Polymers 2020, 12(11), 2476; https://doi.org/10.3390/polym12112476
Received: 20 September 2020 / Revised: 20 October 2020 / Accepted: 22 October 2020 / Published: 25 October 2020
(This article belongs to the Special Issue Thermoresponsive Polymers)
Physically crosslinked low-temperature elastomers were prepared based on linear polydimethylsiloxane (PDMS) elastic chains terminated on both ends with mesogenic building blocks (LC) of azobenzene type. They are generally (and also structurally) highly different from the well-studied LC polymer networks (light-sensitive actuators). The LC units also make up only a small volume fraction in our materials and they do not generate elastic energy upon irradiation, but they act as physical crosslinkers with thermotropic properties. Our elastomers lack permanent chemical crosslinks—their structure is fully linear. The aggregation of the relatively rare, small, and spatially separated terminal LC units nevertheless proved to be a considerably strong crosslinking mechanism. The most attractive product displays a rubber plateau extending over 100 °C, melts near 8 °C, and is soluble in organic solvents. The self-assembly (via LC aggregation) of the copolymer molecules leads to a distinctly lamellar structure indicated by X-ray diffraction (XRD). This structure persists also in melt (polarized light microscopy, XRD), where 1–2 thermotropic transitions occur. The interesting effects of the properties of this lamellar structure on viscoelastic and rheological properties in the rubbery and in the melt state are discussed in a follow-up paper (“Part II”). The copolymers might be of interest as passive smart materials, especially as temperature-controlled elastic/viscoelastic mechanical coupling. Our study focuses on the comparison of physical properties and structure–property relationships in three systems with elastic PDMS segments of different length (8.6, 16.3, and 64.4 repeat units). View Full-Text
Keywords: reversible networks; self-assembly; self-healing; liquid crystals; smart materials reversible networks; self-assembly; self-healing; liquid crystals; smart materials
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MDPI and ACS Style

Horodecka, S.; Strachota, A.; Mossety-Leszczak, B.; Strachota, B.; Šlouf, M.; Zhigunov, A.; Vyroubalová, M.; Kaňková, D.; Netopilík, M.; Walterová, Z. Low-Temperature Meltable Elastomers Based on Linear Polydimethylsiloxane Chains Alpha, Omega-Terminated with Mesogenic Groups as Physical Crosslinkers: A Passive Smart Material with Potential as Viscoelastic Coupling. Part I: Synthesis and Phase Behavior. Polymers 2020, 12, 2476. https://doi.org/10.3390/polym12112476

AMA Style

Horodecka S, Strachota A, Mossety-Leszczak B, Strachota B, Šlouf M, Zhigunov A, Vyroubalová M, Kaňková D, Netopilík M, Walterová Z. Low-Temperature Meltable Elastomers Based on Linear Polydimethylsiloxane Chains Alpha, Omega-Terminated with Mesogenic Groups as Physical Crosslinkers: A Passive Smart Material with Potential as Viscoelastic Coupling. Part I: Synthesis and Phase Behavior. Polymers. 2020; 12(11):2476. https://doi.org/10.3390/polym12112476

Chicago/Turabian Style

Horodecka, Sabina, Adam Strachota, Beata Mossety-Leszczak, Beata Strachota, Miroslav Šlouf, Alexander Zhigunov, Michaela Vyroubalová, Dana Kaňková, Miloš Netopilík, and Zuzana Walterová. 2020. "Low-Temperature Meltable Elastomers Based on Linear Polydimethylsiloxane Chains Alpha, Omega-Terminated with Mesogenic Groups as Physical Crosslinkers: A Passive Smart Material with Potential as Viscoelastic Coupling. Part I: Synthesis and Phase Behavior" Polymers 12, no. 11: 2476. https://doi.org/10.3390/polym12112476

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