Cyclosiloxane polymer bearing dynamic boronic acid: synthesis and bottom-up nanocoating

Kim, Soyeon; Zhu, Huie; Demirci, Ali; Yamamoto, S.; Miyashita, Tokujı; Mitsuishi, Masaya

doi:10.1039/c9py00855a

Cited by 13 publications

(27 citation statements)

References 58 publications

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“…These values are higher than that of linear PDMS (about −120 °C) because of the constraints of segmental motions caused by the steric hindrance of the cyclic TMCS units. It is noteworthy that the residual Si–H groups in the prepolymers endow many possibilities for additional functionalization because it undergoes many reactions including Pt-catalyzed hydrosilylation reactions for the introduction of side-chain functional pendants, ,,− catalyst-free self-condensation cross-linking for free-standing films, , PR reaction, metal-free vulcanization by α-diketones, etc. They are also soluble in numerous organic solvents such as chloroform, toluene, THF, and acetone.…”

Section: Resultsmentioning

confidence: 99%

Effects of Hydride Transfer Ring-Opening Reaction on B(C₆F₅)₃ Catalyzed Polymerization of D₄^H Cyclosiloxane and Dialkoxysilanes toward Thermally Stable Silsesquioxane–Siloxane Hybrid Materials

et al. 2022

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The Piers–Rubinsztajn (PR) reaction catalyzed by a metal-free B(C6F5)3 catalyst was reported as efficient in synthesizing novel polysiloxanes through polycondensation of dialkoxylsilanes and dihydrosiloxane monomers at room temperature. This study is aimed at developing new cyclosiloxane polymers having no hydrocarbon linker in the main chain via an equimolar PR reaction between tetrafunctional eight-membered cyclosiloxanes (TMCS) having the four reactive silyl hydrides (Si–H) at the Si vertices and bifunctional dialkoxylsilanes. The final polymers were targeted with the remaining Si–H group at the Si vertices of the TMCS repeating units for post-functionalization, good solubility in typical organic solvents for post-processing, and a stable ring structure in TMCS for outstanding macromolecular flexibility. However, hydride transfer ring-opening polymerization (HTRP) of TMCS was reported in the B(C6F5)3-catalyzed reaction system, which invariably causes uncontrollable gelation. Suppression of HTRP succeeded via control of total monomer concentration and reaction time reduction, thereby obtaining post-processable and post-functionalizable liquid cyclosiloxane prepolymers. Thermal curing of the prepolymers through self-cross-linking of the remaining reactive Si–H groups gave rise to free-standing films with excellent thermal stability exceeding 600 °C and a low dielectric constant. The functional versatility of the Si–H groups produces promising prepolymers for creating various functional materials.

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Section: Resultsmentioning

confidence: 99%

Effects of Hydride Transfer Ring-Opening Reaction on B(C₆F₅)₃ Catalyzed Polymerization of D₄^H Cyclosiloxane and Dialkoxysilanes toward Thermally Stable Silsesquioxane–Siloxane Hybrid Materials

et al. 2022

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“…A single molecule includes four peripheral catechol groups, four carboxyl groups, and four amide groups bridging the catechol groups with the hydrophobic cyclosiloxane core (Figure b). As explained in the Introduction section, the molecular architecture can use the carboxyl side chain buffering effect and can produce a hydrophobic environment from the TMCS core , simultaneously to maintain the reduced form of catechol. The special molecular architecture will also supply collective intermolecular/intramolecular interactions including catechol–catechol, carboxyl–carboxyl, catechol–carboxyl, and amide–amide hydrogen-bonding (H-bonding) interactions (Figure c).…”

Section: Resultsmentioning

confidence: 99%

Robust, Reusable, and Antioxidative Supramolecular Adhesive to Inorganic Surfaces Based on Water-Stimulated Hydrogen Bonding

Zhu

Demirci

Liu

et al. 2022

ACS Appl. Polym. Mater.

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Reusable adhesives able to bond and debond to a surface as needed in response to stimuli are eagerly sought. Despite recent advances in catechol-derived adhesives, achieving strong and switchable adhesion persists as a challenge because easy catechol-to-quinone oxidation invariably reduces the adhesive catechol units which induce the formation of irreversible cross-linked networks. For this study, a supramolecular adhesive carrying a hydrophobic tetramethylcyclotetrasiloxane (TMCS) core surrounded by hydrophilic groups including four peripheral catechol groups (Cat) and four carboxyl groups (CGs) was demonstrated to have good oxidation resistance and strong and reusable adhesion to inorganic surfaces upon contacting water. The hydrophobic TMCS core supplied a hydrophobic environment for oxidation resistance. Once water was added to the materials, TMCS expelled water to expose more catechol units outward for sufficient contact with the substrate surface. The supramolecule was found to have a remarkably high complex viscosity of up to 2.6 × 108 mPa·s at 1 Hz, which is 105 times that of the TMCS core. These unique properties make the supramolecular material a promising candidate for extensive applications such as marine adhesives.

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“…The CFPS layer (30 nm thickness) was deposited onto the PMMA substrate through a dip coating process. It is noteworthy that our cyclosiloxane‐based polymers have good nanofilm formation capability: uniform coating with 6 nm film thickness on plastic substrates through dip‐coating method 35 . The ZnO NPs dispersion was spin‐coated onto the CFPS layer.…”

Section: Resultsmentioning

confidence: 99%

Flexible ultraviolet detector with robust ZnO nanoparticle nanoassemblies on catechol‐functionalized polysiloxane nanofilms

Liu

Zhu

Watanabe

et al. 2021

J of Applied Polymer Sci

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As a result of the vast Young's moduli difference between an inorganic semiconducting channel and flexible substrates, flexible optoelectronic devices readily lose their functionality through material delamination and local fracturing, which lead to short‐circuiting of devices. For this study, we synthesized a catechol‐containing polysiloxane (CFPS) adhesive and applied it to ZnO nanoparticle (NP) assembly on plastic substrates for flexible UV detector applications. The 30 nm thick CFPS adhesive can anchor 70 nm thick ZnO NPs strongly through a coordination bond, thereby forming an ultra‐stable ZnO NP channel layer. A peeling test of ZnO NP layer was conducted using transparent tape (Scotch®; 3 M Inc.). The ZnO NPs were firmly immobilized, reflecting the outstanding mechanical stability of CFPS adhesives. A UV detector also exhibited stable photo‐response performance even after a thousand iterations of bending with 3 mm curvature radii. The result indicates the polycyclosiloxane‐based flexible device as promising for wearable detector applications.

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Cyclosiloxane polymer bearing dynamic boronic acid: synthesis and bottom-up nanocoating

Abstract: Boronic acid-containing polycyclosiloxane showed unique self-assembly nanofilm formation (6 nm film thickness) on various substrates and provided film-based metal ion sensor capability through dynamic covalent bonding.

Cited by 13 publications

References 58 publications

Effects of Hydride Transfer Ring-Opening Reaction on B(C₆F₅)₃ Catalyzed Polymerization of D₄^H Cyclosiloxane and Dialkoxysilanes toward Thermally Stable Silsesquioxane–Siloxane Hybrid Materials

Effects of Hydride Transfer Ring-Opening Reaction on B(C₆F₅)₃ Catalyzed Polymerization of D₄^H Cyclosiloxane and Dialkoxysilanes toward Thermally Stable Silsesquioxane–Siloxane Hybrid Materials

Robust, Reusable, and Antioxidative Supramolecular Adhesive to Inorganic Surfaces Based on Water-Stimulated Hydrogen Bonding

Flexible ultraviolet detector with robust ZnO nanoparticle nanoassemblies on catechol‐functionalized polysiloxane nanofilms

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Cyclosiloxane polymer bearing dynamic boronic acid: synthesis and bottom-up nanocoating

Abstract: Boronic acid-containing polycyclosiloxane showed unique self-assembly nanofilm formation (6 nm film thickness) on various substrates and provided film-based metal ion sensor capability through dynamic covalent bonding.

Cited by 13 publications

References 58 publications

Effects of Hydride Transfer Ring-Opening Reaction on B(C6F5)3 Catalyzed Polymerization of D4H Cyclosiloxane and Dialkoxysilanes toward Thermally Stable Silsesquioxane–Siloxane Hybrid Materials

Effects of Hydride Transfer Ring-Opening Reaction on B(C6F5)3 Catalyzed Polymerization of D4H Cyclosiloxane and Dialkoxysilanes toward Thermally Stable Silsesquioxane–Siloxane Hybrid Materials

Robust, Reusable, and Antioxidative Supramolecular Adhesive to Inorganic Surfaces Based on Water-Stimulated Hydrogen Bonding

Flexible ultraviolet detector with robust ZnO nanoparticle nanoassemblies on catechol‐functionalized polysiloxane nanofilms

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Effects of Hydride Transfer Ring-Opening Reaction on B(C₆F₅)₃ Catalyzed Polymerization of D₄^H Cyclosiloxane and Dialkoxysilanes toward Thermally Stable Silsesquioxane–Siloxane Hybrid Materials

Effects of Hydride Transfer Ring-Opening Reaction on B(C₆F₅)₃ Catalyzed Polymerization of D₄^H Cyclosiloxane and Dialkoxysilanes toward Thermally Stable Silsesquioxane–Siloxane Hybrid Materials