Functionalized Molecular Bottlebrushes

Gadwal, Ikhlas; Rao, Jingyi; Baettig, Julia; Khan, Arijit

doi:10.1021/ma402259q

Cited by 61 publications

(47 citation statements)

References 90 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The enhanced steric repulsion between the densely grafted side chains forces the main chains to elongate. They were successfully synthesized via several grafting strategies, including "graft-through" [6][7][8][9][10][17][18][19][20] , "graft-from" 4,5,12,13,21,22 , "graft-to" [23][24][25] , as well as their varied combinations 26 , which have been summarized in recent reviews 2,3 . During the past decades, polymer molecular brushes have received progressively growing attention.…”

Section: Introductionmentioning

confidence: 99%

Efficient synthesis of narrowly dispersed amphiphilic double-brush copolymers through the polymerization reaction of macromonomer micelle emulsifiers at the oil–water interface

Han

Gao

et al. 2016

Polym. Chem.

View full text Add to dashboard Cite

In this study, well-defined amphiphilic double-brush copolymers (DBCs) with narrow molecular weight distributions were efficiently synthesized by radical polymerization of macromonomers directed by Pickering emulsion template at oil-water interface.Firstly, well-defined poly(methyl methacrylate)-b-poly(N,N-dimethyl acryamide) (PMMA-b-PDMA) diblock macromonomer carrying a pendent methacryloyl (MA) group at the block junction (MA-PMMA-b-PDMA) was synthesized through sequential atom transfer radical polymerization (ATRP) and reversible addition-fragmentation chain transfer (RAFT) polymerization, followed by an acrylation functionalization reaction. The MA-PMMA-b-PDMA macromonomer could self-assemble into core-shell micelles with hydrophobic PMMA-based cores, hydrophilic PDMA shells and MA groups at core-shell boundary. The as-formed core-shell micelles were then employed as emulsifiers for the formation of stabilized oil-in-water (o/w) Pickering emulsion, in which the macromonomer micelles were locked at the oil-water interface and presented Janus-like conformation. At last, the conventional radical polymerization reaction was carried out for the MA groups of the macromonomer micelles absorbed at the oil-water interface using azobiisobutyronitrile (AIBN) pre-encapsulated in the Pickering emulsion oil droplets as initiator, leading to well-defined PMA-g-PMMA/PDMA DBCs with narrow molecular weight distributions. The as-formed DBCs showed higher degrees of polymerization of backbones than the DBCs synthesized by micellar polymerization of the macromonomer in pure water, presumably due to the facilitated propagation reaction between the neighboring micelles in the former cases. The macromonomers and DBCs were carefully characterized by various instrumental analytical techniques. displayed the 1 H NMR spectra of BEMP and BMBP. For BEMP, the respective resonances were clearly assigned, which were in good agreement with the early reports 40 . Different with the 1 H NMR spectrum of BEMP, the spectrum of BMBP showed new resonances at 4.15-4.07 and 1.94 ppm. These resonances were assigned to the methylene protons of -C(Br)COOCH 2 group and the methyl protons of -C(Br)CH 3 group, respectively. The 1 H NMR results confirmed that the designed BMBP was successfully synthesized. Scheme 2. Synthesis routes of BEMP, BMBP, PMMA, PMMA-b-PDMA, MA-PMMA-b-PDMA, and PMA-g-PMMA/PDMA. (i) EMP/DCC/DMAP/acetone, room temperature; (ii) 2-bromoisobutyryl bromide/Et 3 N/CH 2 Cl 2 , room temperature; (iii) MMA/CuBr/PMDETA/anisole; (iv) DMA/AIBN/DMF; (v) methacryloyl chloride,Et 3 N/CH 2 Cl 2 ; (vi) AIBN/70 ℃.Fig. 4 (A) Volume-average distribution of the hydrodynamic diameters of macromonomer micelles in water; (B) TEM image of macromonomer micelles without staining; (C,D) TEM images of macromonomer micelles stained by phosphotungstic acid solution. Core crosslinked star-like (CCS) polymer nanoparticles exhibited excellent emulsifying performances, and can allow for the generation of highly stabilized Pickering emulsions at extremely low contents ...

show abstract

Section: Introductionmentioning

confidence: 99%

Efficient synthesis of narrowly dispersed amphiphilic double-brush copolymers through the polymerization reaction of macromonomer micelle emulsifiers at the oil–water interface

Han

Gao

et al. 2016

Polym. Chem.

View full text Add to dashboard Cite

show abstract

“…These characteristics have allowed for the discovery of innovative solutions in the field of coatings technology [4,5]. Among click reactions, thiol-epoxy systems have broad applications [6][7][8][9][10][11] but they present an important drawback which is the low reactivity of the formulation that requires the addition of a catalyst. However, the disadvantage of a too short pot-life appears on catalysing with amines [12].…”

Section: Introductionmentioning

confidence: 99%

Enhancement in the Glass Transition Temperature in Latent Thiol-Epoxy Click Cured Thermosets

et al. 2015

View full text Add to dashboard Cite

Tri and tetrafunctional thiol were used as curing agent for diglycidyl ether of bisphenol A (DGEBA) catalyzed by a commercially available amine precursor, LC-80. Triglycidyl isocianurate (TGIC) was added in different proportions to the mixture to increase rigidity and glass transition temperature (Tg). The cooperative effect of increasing functionality of thiol and the presence of TGIC in the formulation leads to an increased Tg without affecting thermal stability. The kinetics of the curing of mixtures was studied by calorimetry under isothermal and non-isothermal conditions. The latent characteristics of the formulations containing amine precursors were investigated by rheometry and calorimetry. The increase in the functionality of the thiol produces a slight decrease in the storage lifetime of the mixture. The materials obtained with tetrathiol as curing agent showed the highest values of Young's modulus and Tg.

show abstract

“…There are mainly three strategies in synthesizing well‐defined bottlebrushes: “grafting from”, “grafting through”, and “grafting onto” . By using these strategies, linear, star, and “sun‐shaped” bottlebrush (co)polymers have been prepared, respectively . In the past couple of decades, the structure of bottlebrushes, especially the “graft density”, has been particularly investigated for its remarkable influence on polymers' properties.…”

Section: Introductionmentioning

confidence: 99%

Synthesis of Bottlebrush Polystyrenes with Uniform, Alternating, and Gradient Distributions of Brushes Via Living Anionic Polymerization and Hydrosilylation

Wang

Sang

et al. 2015

Macromol. Rapid Commun.

View full text Add to dashboard Cite

By combining living anionic polymerization and hydrosilylation, densely grafted bottlebrush polymers with controlled spacing of branch points are prepared. Dimethyl(4-vinylphenyl)silane and dimethyl(4-(1-phenylvinyl)phenyl)silane are anionically (co)polymerized to synthesize uniform, alternating, and gradient in-chain silyl-hydride (Si-H) functionalized backbones. The spacing of branch points is controlled effectively by regulating the distribution of Si-H groups along the backbones. Three backbones with a similar number of Si-H groups but variable distributions are used to synthesize corresponding bottlebrush polymers via hydrosilylation between the backbones and chain-end vinyl functionalized polystyrene. The uniformly grafted bottlebrush exhibits the highest hydrodynamic radius (Rh ) of 5.6 nm and the lowest Tg of 79 °C which may be attributed to its compact grafted structure. This methodology exhibits high efficiency and convenience for the construction of bottlebrushes with controlled distribution of brushes.

show abstract

Functionalized Molecular Bottlebrushes

Cited by 61 publications

References 90 publications

Efficient synthesis of narrowly dispersed amphiphilic double-brush copolymers through the polymerization reaction of macromonomer micelle emulsifiers at the oil–water interface

Efficient synthesis of narrowly dispersed amphiphilic double-brush copolymers through the polymerization reaction of macromonomer micelle emulsifiers at the oil–water interface

Enhancement in the Glass Transition Temperature in Latent Thiol-Epoxy Click Cured Thermosets

Synthesis of Bottlebrush Polystyrenes with Uniform, Alternating, and Gradient Distributions of Brushes Via Living Anionic Polymerization and Hydrosilylation

Contact Info

Product

Resources

About