Tailoring block copolymer morphologies via alkyne/azide cycloaddition

Abstract

We investigated the morphological transitions induced by alkyne/azide Huisgen 1,3-dipolar cycloaddition reaction in a series of poly(ethylene oxide)-block-poly(n-butyl methacrylate-random-propargyl methacrylate) (PEO-b-P(nBMA-r-PgMA)) diblock copolymers. Studies on the phase behavior of neat diblock copolymers revealed that the interactions between the PEO block and the terminal alkyne groups in the P(nBMA-r-PgMA) block significantly affected the miscibility between the two blocks and the crystallization of the PEO block. Phase-mixed diblock copolymers underwent disorder-to-order transitions by blending with Rhodamine B azide and annealing at elevated temperatures. Different morphologies were achieved, not only by controlling the composition of the block copolymer but also by blending the diblock copolymer with different amount of azides. Microphase separated PEO-b-P(nBMA-r-PgMA) diblock copolymer also exhibited reactivity toward azides, and order-to-order transitions were observed. V C 2011 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 50: [55][56][57][58][59][60][61][62][63][64] 2012 Previously, we reported a DOT induced by alkyne/azide Huisgen 1,3-dipolar cycloaddition in a binary blend of the alkyne-bearing di-BCP poly(ethylene oxide)-block-poly(nbutyl methacrylate-random-propargyl methacrylate) (PEO-b-P(nBMA-r-PgMA)) and Rhodamine B azide. 34 During thermal annealing, the alkyne groups in the P(nBMA-r-PgMA) block were coupled with the azide compound (Scheme 1). The change in chemical structure of the di-BCP significantly increased the nonfavorable interactions between the two Additional Supporting Information may be found in the online version of this article.

Well-defined “clickable” copolymers prepared via one-pot synthesis

“…Consequently, when using living or controlled polymerisation techniques the propargylgroup is usually protected and then de-protected after the polymer is recovered. [5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20] For example by using atom-transfer radical polymerisation (ATRP) to polymerise the protected form of PMA (trimethylsilyl-PMA, TMSPMA) a homopolymer with PDI = 1.20 was produced, 18 while direct homopolymerisation of PMA resulted in polymers with very high PDIs (43) and crosslinked networks. 21 When PA was copolymerised with N-isopropylacrylamide (NIPAm) using ATRP and a poly(ethylene glycol), PEG-macroinitiator, a copolymer with a narrow PDI of 1.09 was produced.…”

Synthesis and Characterization of Amine-Epoxy-Functionalized Polystyrene-block-Poly(glycidyl methacrylate) to Manage Morphology and Covarying Properties for Self-Assembly

“…5 Subsequently, they tuned the volume fraction of their PEO block and the alkyne/azide ratio in their system, akin to f S and φ C in the work reported here, and showed with the appropriate starting BCP that they could generate either lamellar or cylindrical morphologies, depending on the alkyne/azide ratio. 40 The work here also uses click chemistry to access different morphologies in the phase diagram, but it differs in that reaction to completion of one of the blocks with two different amines provides a much broader array of possibilities in terms of attainable chemistries and their corresponding χ values.…”

Disorder-to-order transitions induced by alkyne/azide click chemistry in diblock copolymer thin films

“…In the corresponding bulk sample, hexagonally packed cylindrical microdomains were observed after thermal annealing. 64 In thin films, after annealing for 12 h at 110 C and 130 C, respectively, circular structures were observed on the top surface (Fig. 3 (a), (b)), and sharp Bragg rod scattering peaks along q z were seen in the GISAXS pattern (Fig.…”

“…However, for the two di-BCPs investigated here, at different alkyne/azide mole ratios, the microphase separated morphologies are always of the same type, as long as the azide loading ratio is above a critical value ($25%). 64 Here we also investigated the effects of the alkyne/azide mole ratio on the morphologies in thin films. Fig.…”