Preparation and characterization of an azide–alkyne cycloaddition based self-healing system via a semiencapsulation method

Saikia, Basanta; Dolui, Swapan Kumar

doi:10.1039/c5ra17666b

Cited by 13 publications

(11 citation statements)

References 39 publications

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“…The immobilization of the PSt 8 - h -P4VP 8 copolymer monolayer over the modified PDMS channel was carried out in two steps. First, the channel was further functionalized with bromoalkyl by injecting a 10% 3-bromopropyltrimethoxysilane (Br-PTMS) solution at 60 °C for 3 h. The presence of the C–Br bond was confirmed by FT-IR spectra at 691 cm –1 (Figure S24) and Br 3d (Figure S25) by X-ray photoelectron spectra at 71.5 eV. , The PSt 8 - h -P4VP 8 copolymer was then mounted by a quaternization reaction between the bromoalkyl and the terminal pyridine of the P4VP arms via a “grafting-to” approach.…”

Section: Resultsmentioning

confidence: 99%

Flow-Assisted Switchable Catalysis of Metal Ions in a Microenvelope System Embedded with Core–Shell Polymers

Vishwakarma

Hwang

Adiyala

et al. 2018

ACS Appl. Mater. Interfaces

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Many efforts have been made on stimuliresponsive switchable catalysis to trigger catalytic activity over various chemical reactions. However, the reported light-, pHor chemically responsive organocatalysts are mostly incomplete in the aspects of shielding efficiency and long-term performance. Here, we advance the flow-assisted switchable catalysis of metal ions in a microenvelope system that allows the on−off catalysis mode on demand for long-lasting catalytic activity. Various metal-ion catalysts can be selectively embedded in a novel polymeric core−shell of the heteroarm star copolymer of poly(styrene) and poly(4-vinylpyridine) emanated from a polyhedral oligomeric silsesquioxane center. The immobilized core−shell polymer on the inner wall of a poly(dimethylsiloxane) envelope microreactor shows on−off switching catalysis between the expanded active mode and contracted protective mode under continuous flow of solvents or subsequent dry conditions. In particular, the preserved catalytic activity of toxic Hg 2+ for oxymercuration was demonstrated even for 2 weeks without leaching, whereas the activity of moisture-sensitive Ru 3+ ions for polymerization of methyl methacrylate was maintained even after 5 days from an open atmosphere. It is practical that the tight environment of the enveloped microfluidic system facilitates cyclic switching between the reaction-"on" and -"off" modes of such toxic, sensitive/expensive catalysts for long-term prevention and preservation.

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Section: Resultsmentioning

confidence: 99%

Flow-Assisted Switchable Catalysis of Metal Ions in a Microenvelope System Embedded with Core–Shell Polymers

Vishwakarma

Hwang

Adiyala

et al. 2018

ACS Appl. Mater. Interfaces

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“…Size distribution histogram of the microcapsules determined by dynamic light scattering is shown in the Figure . Size of the microcapsule was found to be in a wide range which may be due to the fact that the fluid flow around the propeller is turbulent, in the region of flow away from the propeller, many larger microeddies exist, and in the vicinity of the propeller blades, many smaller microeddies exist, resulting a wider capsule size distribution . The mean diameter of the prepared MF microcapsules was found to be ∼110 µm, which is adequate for using in self‐healing of material.…”

Section: Resultsmentioning

confidence: 98%

Designing semiencapsulation based covalently self‐healable poly(methyl methacrylate) composites by Atom Transfer Radical Polymerization

Saikia

Dolui

2016

J. Polym. Sci. Part A: Polym. Chem.

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Self-healable poly(methyl methacrylate) (PMMA) composites were fabricated with embedded glycidyl methacrylate (GMA) encapsulated poly(melamine-formaldehyde) microcapsules. The matrix polymers were synthesized via Atom Transfer Radical Polymerization using two different initiators; one linear and another hexafunctional. As the so prepared polymer matrix retains living characteristics, it can initiate a healing reaction when the encapsulated monomer reaches the matrix due to formation or extension of a crack and thus healing the system covalently. The effect of number of initiating functionality on healing characteristic was studied using both linear and 6-armed star PMMA having same targeted molecular weight. Both the systems were able to restore 100% original fracture toughness after healing. However, the polymer matrix prepared by hexafunctional initiator restored the fracture toughness much faster than that of the linear polymer matrix.

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“…Akhan et al (16) preformed a survey of one healing agent (azide compound)-contained capsule on an alkyne-graphene oxide matrix with the use of CuAAC click reaction, leading to improving the self-healing efficiency through an incorporation of the low molecular weight selfhealing agent within the microcapsule. Besides, Saikia et al (18) designed an azide-alkyne cycloaddition-based SHMs through azide-multiwall carbon nanotubes with poly(t-butyl acrylate) and alkyne compound-contained capsule embedded in an epoxy matrix, manifesting that this SHM recovered as much as 65% of its original fracture toughness. Herein, the self-healing ability of the as-prepared PU/MCs-based SHMs on the basic of only one type of healing agent (alkyne compound)contained capsule is surveyed through various weight ratios of MCs and cracks.…”

Section: Self-healing Ability Of Pu/mcs-based Shmsmentioning

confidence: 99%

“…As limitation of the use of CuAAc regrading to diffusion of the participating reactants, Dohler et al (17) performed more extensively in variety of multivalent azide/alkyne compounds and polymers grafted with various molecular weights, viscosities, and functional group densities. Further, Saikia et al (18) also designed an azide-alkyne cycloaddition-based SHMs through azide-multiwall carbon nanotubes with poly(t-butyl acrylate) and alkyne compound-contained capsule embedded in an epoxy matrix. On the basic of any damaging event occurs in the epoxy matrix, the healing liquid could dissolve the implanted catalyst from the matrix to occur the crosslinking reaction between azide and alkyne leading to healing the cracks, as well as investigated the influences of temperature and healing time (18).…”

Section: Introductionmentioning

confidence: 99%

“…Further, Saikia et al (18) also designed an azide-alkyne cycloaddition-based SHMs through azide-multiwall carbon nanotubes with poly(t-butyl acrylate) and alkyne compound-contained capsule embedded in an epoxy matrix. On the basic of any damaging event occurs in the epoxy matrix, the healing liquid could dissolve the implanted catalyst from the matrix to occur the crosslinking reaction between azide and alkyne leading to healing the cracks, as well as investigated the influences of temperature and healing time (18). Thereby, a terminal alkyne compound BPS is concerned as a healing agent to be used as a core material, and poly(urea-formaldehyde) (PUF) is employed as a wall shell.…”

Section: Introductionmentioning

confidence: 99%

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A Self-Healing Material Based on Microcapsules of Poly(Urea-Formaldehyde)/Bis-Propargyl-Succinate Containing in Polyurethane Matrix

Vo¹,

Vo²

2021

Journal of the Turkish Chemical Society Section A: Chemistry

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With the development of current technology, several concepts of self-healing materials (SHMs) have recently been proposed, and capsule-based SHMs are explored. In our study, a terminal alkyne compound (bis-propargyl-succinate, BPS) is concerned as a healing agent to be used as a core material, and poly(urea-formaldehyde) (PUF) is employed as a wall shell. Besides, the chemical, morphological and thermal properties of the microcapsules (MCs) are also determined by Fouriertransform infrared spectroscopy (FTIR), gas chromatography (GC), thermogravimetric analysis (TGA), and optical microscopy (OM). Additionally, the MCs have better thermal stability up to 257 °C with the rough outer surface. The MCs have successfully encapsulated 75.0% of BPS with a size range of 63 -125 μm and PUF shell thickness range of 5.72 -11.35 μm; moreover, the stability of MCs is well maintained within 50 days at room temperature basing on the solvent extraction method. Concomitantly, self-healing ability is activated by the breakup of the MCs as cracks, then the healing agent (BPS) is released into the cracked regions to react with azide groups of the polymeric matrix. The BPS in the MCs is moved to cracked regions, which involves MCs diameter and weight fraction of PUF capsules. Moreover, the self-healing ability can reach high when BPS amounts (i.e., SHMs containing 5% and 10% of MCs) are available sufficiently to be outrightly filled into the cracked regions. Thereby, MCs' size and weight fraction can be reasonably selected to result in an optimal healing capacity for a preestablished size of cracks.

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Preparation and characterization of an azide–alkyne cycloaddition based self-healing system via a semiencapsulation method

Abstract: An azide–alkyne cycloaddition based self-healing system was designed by a semiencapsulation method.

Cited by 13 publications

References 39 publications

Flow-Assisted Switchable Catalysis of Metal Ions in a Microenvelope System Embedded with Core–Shell Polymers

Flow-Assisted Switchable Catalysis of Metal Ions in a Microenvelope System Embedded with Core–Shell Polymers

Designing semiencapsulation based covalently self‐healable poly(methyl methacrylate) composites by Atom Transfer Radical Polymerization

A Self-Healing Material Based on Microcapsules of Poly(Urea-Formaldehyde)/Bis-Propargyl-Succinate Containing in Polyurethane Matrix

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