H-bonding tuned phase transitions of a strong microphase-separated polydimethylsiloxane-b-poly(2-vinylpyridine) block copolymer. (26th September 2018)

• Record Type: Journal Article
• Authors: Shi, Ling-Ying; Lei, Wei-Wei; Liao, Fen; Chen, Jing; Wu, Meng; Zhang, Yi-Yi; Hu, Chen-Xin; Xing, Lu; Zhang, Yu-Lin; Ran, Rong
• Is Part Of: Polymer. Volume 153(2018)
• Page Start: 277
• Page End: 286
• Publication Date: 2018-09-26
• Subjects: Block copolymer -- Supramolecular self-assembly -- H-bonding -- Phase transition; Polymers -- Periodicals; Polymerization -- Periodicals; Polymères -- Périodiques; Polymérisation -- Périodiques; 547.7
• DOI: 10.1016/j.polymer.2018.02.003
• Languages: English
• ISSNs: 0032-3861

Abstract

Abstract: The phase behaviors of a polydimethylsiloxane- b -poly(2-vinylpyridine) block copolymer (PDMS- b -P2VP, DV) tuned by the supramolecular self-assembly approach with the 1-pyrenebutyric acid (PBA) as additive were investigated. The PDMS- b -P2VP block copolymer (D10k V12.5k, the molecular weight of the PDMS and P2VP were 10000 and 12500 g mol −1, respectively) with volume fraction of P2VP ( f P2VP ) 52% exhibited hexagonally perforated layer (HPL) morphology after dried from the solution, and the nanostructure transformed to gyroid structure after thermal annealing above 140 o C, which were indicated by the small-angle X-ray diffraction (SAXS) and transmission electron microscopy (TEM) results. Through solution blending method, a series of H-bonding supramolecular complexes of PDMS- b -P2VP with PBA were fabricated. The Fourier transform infrared (FTIR) spectroscopy and differential scanning calorimetry (DSC) experiments demonstrated that the PBA molecules uniformly interacted with P2VP through H-bonding and the glass transition temperature of P2VP(PBA) x decreased with the increase of the mole ratio ( x ) of PBA/2VP. Due to the increase of the volume fraction of P2VP(PBA) x and that of the stretching extent of the P2VP backbone as the x value increased, the microphase-separated nanostructures transformed from HPL to hexagonally packed cylinder (HEX), then to body centered cubic (BCC) structure and then to disordered spheres morphologies. When the PDMS- b -P2VP(PBA) x complexes were heated above 120 o C, the H-bonding between the P2VP and PBA was broken and the PBA became compatible within both PDMS and P2VP domains and thus the nanostructure of the PDMS- b -P2VP(PBA) x complexes transformed accordingly. Therefore, a variety of the nanostructures and structural transformations were induced by the H-bonding formation and disassociation based on one block copolymer. Graphical abstract: Varieties of nanostructures and structure transitions were obtained based on a strong microphase-separated block copolymer tuned by H-bonding formation and dissociation. Image 1 Highlights: The strong microphase-separated PDMS- b -P2VP BCP, with f P2VP ∼52% exhibited hexagonally perforated layer (HPL) morphology. The phase behavior of PDMS- b -P2VP was tuned by the supramolecular self-assembly approach with the PBA as additives. The T g of P2VP decreased when it was H-bonded with PBA. Rich variety of the nanostructures and structural transformations were induced by the H-bonding formation and disassociation.