Tuning Dispersity in Diblock Copolymers Using ARGET ATRP

Plichta, Andrzej; Zhong, Mingjiang; Li, Wenwen; Elsen, Andrea M.; Matyjaszewski, Krzysztof

doi:10.1002/macp.201200461

Cited by 64 publications

(60 citation statements)

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“…Activators regenerated by electron transfer (ARGET) ATRP [29][30][31] is capable of tuning the MWDs of synthesized polymers by the catalyst concentration. [ 32,33 ] Recently reported computational studies indicated that copolymers with large fi nal M w / M n values are characterized by poor gradient quality; [ 34 ] it was the goal of this work to examine this correlation between M w /M n values and gradient quality experimentally. Synthesis of methacrylate/acrylate gradient copolymers was carried out by batch copolymerization under ARGET ATRP conditions in the presence of systematically decreasing catalyst concentrations (Cu II X 2 /L) resulting in decreasing quality of MWD.…”

Section: Synthesis Of Gradient Backbonementioning

confidence: 99%

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Exploring Quality in Gradient Copolymers

Elsen

et al. 2013

Macromol. Rapid Commun.

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Quality of gradient copolymers is evaluated by atomic force microscopy (AFM) and correlated with molecular weight distribution (MWD) values. ARGET ATRP is employed with decreasing levels of catalyst concentrations to generate copolymers with increasing M¯w/M¯n values. The copolymers are transformed into molecular bottlebrushes to enable imaging and analysis of individual molecules by AFM. The average height (cross-sectional) profile of all bottlebrushes agrees with the instantaneous composition (ICHEMA-TMS ) of the analogous copolymer backbone, as determined by (1) H NMR. The copolymer synthesized with 500 ppm of catalyst exhibits more narrow distributions of both brush height and backbone length when analyzed as a bottlebrush by AFM. Correspondingly, the copolymers synthesized with lower catalyst concentrations yield bottlebrushes with broader height and length distribution. These results establish MWD values as an excellent trait to assess quality within gradient copolymers.

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Section: Synthesis Of Gradient Backbonementioning

confidence: 99%

“…This can be relatively easily controlled by concentration of the deactivating species. Activators regenerated by electron transfer (ARGET) ATRP is capable of tuning the MWDs of synthesized polymers by the catalyst concentration …”

Section: Introductionmentioning

confidence: 99%

Exploring Quality in Gradient Copolymers

Elsen

et al. 2013

Macromol. Rapid Commun.

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“…[7][8][9][10][11][12] However,p olymers with large values are occasionally desired for improved physical properties such as miscibility and processability,a nd the manipulation of in LRP is an important topic but still challenging. [16][17][18] However,t he attained large usually arose from inefficient control in LRP. [13][14][15] Thep olymers need to be prepared in multiple independent runs,a nd the blended polymers often have multimodal molecular weight distribution.…”

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Polymer Dispersity Control by Organocatalyzed Living Radical Polymerization

2019

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Molecular weight distribution of polymers,t ermed dispersity (), is af undamental parameter for determining polymer material properties.T his paper reports an ovel approach for controlling by exploiting at emperatureselective radical generation in organocatalyzed living radical polymerization. The polymers with tailored were synthesized in ab atch system without the assistance of an external pump.Aunique aspect of this approach is that was tuneable from 1.11 to 1.50 in any segment in diblock, triblock, and multiblock copolymers and in any form of star and brush polymer without segmental or topological restriction. This approach is amenable to various monomers and free from metals and thus attractive for applications.T he approach also generated polymer brushes on surfaces with tailored .A n interesting finding was that the polymer brushes exhibited unique interaction with external molecules,d epending on the value.Molecular weight distribution of polymers,t ermed dispersity ( = M w /M n ), is afundamental parameter in determining polymer properties such as processability,viscoelasticity,and self-assembly behaviors,w here M w and M n are the weightand number-average molecular weights,r espectively. [1][2][3][4][5][6] Living radical polymerization (LRP) facilitates the synthesis of polymers with small values,a sw ell as pre-determined molecular weights and sophisticated architectures. [7][8][9][10][11][12] However,p olymers with large values are occasionally desired for improved physical properties such as miscibility and processability,a nd the manipulation of in LRP is an important topic but still challenging. Several approaches have been developed to manipulate values.Blending polymers with different molecular weights is often applied. [13][14][15] Thep olymers need to be prepared in multiple independent runs,a nd the blended polymers often have multimodal molecular weight distribution. By optimizing the polymerization conditions such as catalyst loadings, initiators,temperatures,and additional chain-transfer agents, the was modulated at 1.1-2.0 in LRP. [16][17][18] However,t he attained large usually arose from inefficient control in LRP. Thus,t he obtained polymers hardly undergo further chain extension. Recently,F ors et al. elegantly varied and molecular weight distribution "shapes" by metering the addition of an initiator using af eeding pump in anionic and nitroxide-mediated polymerizations. [19][20][21][22] This approach was applied to homopolymers and the first segment of block copolymers but not to the other segments of block copolymers.B oyer et al. recently metered the addition of the polymeric initiator (macro-initiator) in ap hotocontrolled LRP and successfully obtained block copolymers with tailored in the second segment. [23,24] However, the pumpassisted method is always inapplicable to heterogeneous systems,s uch as polymer brush synthesis from solid substrates,a nd thus limits applications.We have developed an organocatalyzed LRP,t hat is, reversible complexation mediated polymerization (RCMP) t...

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“…[29] Despite these great developments,c urrent reported strategies are limited to bimodal molecular weight distributions,a dulterated polymer chains,a nd/or low endgroup fidelity.F or instance,arecent publication has reported the addition of phenylhydrazine over the course of the polymerisation. [32,33] To overcome these challenges,wesought arobust ATRP system where the molecular weight distribution could be controlled by simply tuning the amount of catalyst (copper/ ligand). [30,31] Other systems require the addition of as mall amount (4-10 %) of ad ifferent monomer type to efficiently tailor the dispersity,leading to random copolymers.…”

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confidence: 99%

“…[30][31][32] Matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry (MALDI-ToF-MS) of highdispersity samples can be challenging,asthe samples contain abroad range of different species and ionising high molecular weight polymer chains can be problematic.F or example,due to the high dispersity of our samples,p art of the polymer population exceeds 75 000 gmol À1 according to SEC although the average M n is just % 12 500 gmol À1 .T ocircumvent this and assess the end-group fidelity of the high-dispersity materials, alower degree of polymerisation was also targeted (DP = 10, = 1.52, Figure S12). [30][31][32] Matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry (MALDI-ToF-MS) of highdispersity samples can be challenging,asthe samples contain abroad range of different species and ionising high molecular weight polymer chains can be problematic.F or example,due to the high dispersity of our samples,p art of the polymer population exceeds 75 000 gmol À1 according to SEC although the average M n is just % 12 500 gmol À1 .T ocircumvent this and assess the end-group fidelity of the high-dispersity materials, alower degree of polymerisation was also targeted (DP = 10, = 1.52, Figure S12).…”

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Tuning Dispersity by Photoinduced Atom Transfer Radical Polymerisation: Monomodal Distributions with ppm Copper Concentration

et al. 2019

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Dispersity significantly affects the properties of polymers.H owever,c urrent methods for controlling the polymer dispersity are limited to bimodal molecular weight distributions,a dulterated polymer chains,o rl ow end-group fidelity and rely on feeding reagents,f low-based, or multicomponent systems.T oo vercome these limitations,w er eport as imple batchs ystem wherebyp hotoinduced atom transfer radical polymerisation is exploited as ac onvenient and versatile technique to control dispersity of both homopolymers and blockc opolymers.B yv arying the concentration of the copper complex, awide range of monomodal molecular weight distributions can be obtained ( = 1.05-1.75). In all cases,high end-group fidelity was confirmed by MALDI-ToF-MS and exemplified by efficient blockc opolymer formation (monomodal, = 1.1-1.5). Importantly,o ur approach utilises ppm levels of copper (as low as 4ppm), can be tolerant to oxygen and exhibits perfect temporal control, representing amajor step forwardi nt uning polymer dispersity for various applications.

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Tuning Dispersity in Diblock Copolymers Using ARGET ATRP

Cited by 64 publications

References 57 publications

Exploring Quality in Gradient Copolymers

Exploring Quality in Gradient Copolymers

Polymer Dispersity Control by Organocatalyzed Living Radical Polymerization

Tuning Dispersity by Photoinduced Atom Transfer Radical Polymerisation: Monomodal Distributions with ppm Copper Concentration

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