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Lessard Research Group - Next Generation Materials for Next Generation Applications

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New Publication! poly(styrene-alt-maleic anhydride) containing block copolymers with tunable mechanical properties

New Publication in Macromolecular Research!

Poly(styrene-alt-maleic anhydride)-block-poly(methacrylate-ran-styrene) block copolymers were synthesized from low dispersity (M w /M n =1.24) and perfectly alternating poly(styrene-alt-maleic anhydride) macroinitiators, by nitroxide mediated controlled radical polymerization (NMP), using various methacrylate-rich mixtures: methyl methacrylate/styrene (MMA/S), ethyl methacrylate/styrene (EMMA/S), n-butyl methacrylate/styrene (BMA/S) and benzyl methacrylate/styrene (BzMA/S). Some irreversible termination was present during the chain extension from the macroinitiator, resulting in some bimodality in the molecular weight distribution of the final block copolymer (≈2% to ≈25% dead chains) which is common for methacrylate/styrene copolymerizations by NMP. The resulting final block copolymers were determined to be methacrylate-rich (molar ratio XMA/S ≈3.3 to 5.5) by 1H NMR and the resulting glass transition temperature (T g ) of the chain-extended segments were found to be similar to the coresponding pure poly(methacrylate)s. NMP allows the controlled placement of functional maleic anhydride containing segments within a block copolymer with tunable mechanical properties by simple substitution of methacrylate monomer used in synthesis.

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New Publication! Crystals, crystals, crystals!!!

New publication in Acta Crystalography!

We report the syntheses and characterization of three solution-processable phen­oxy silicon phthalocyanines (SiPcs), namely bis­(3-methyl­phen­oxy)(phthalocyanine)silicon [(3MP)2-SiPc], C46H30N8O2Si, bis­(2-sec-butyl­phen­oxy)(phthalocyanine)silicon [(2secBP)2-SiPc], C44H24I2N8O2Si, and bis­(3-iodo­phen­oxy)(phthalocyanine)silicon [(3IP)2-SiPc], C52H42N8O2Si. Crystals grown of these compounds were characterized by single-crystal X-ray diffraction and the -inter­actions between the aromatic SiPc cores were studied. It was determined that (3MP)2-SiPc has similar inter­actions to previously reported bis­(3,4,5-tri­fluoro­phen­oxy)silicon phthalocyanines [(345 F)2-SiPc] with significant - inter­actions between the SiPc groups. (3IP)2-SiPc and (2secBP)2-SiPc both experienced a parallel stacking of two of the peripheral aromatic groups. In all three cases, the solubility of these mol­ecules was increased by the addition of phen­oxy groups while maintaining pi - pi inter­actions between the aromatic SiPc groups. The solubility of (2secBP)2-SiPc was significantly higher than other bis-phen­oxy-SiPcs and this was exemplified by the higher observed disorder within the crystal structure.

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New publication! Changing the morphology: the addition of thiophenes!

New Publication in Journal of Polymer Research

Thiophene decorated block copolymers templated from poly(styrene-alt-maleic anhydride)-block-poly(styrene) one-shot block copolymer: effect of thiophene inclusion on morphology

Poly(styrene-alt-maleic anhydride) copolymer and poly(styrene-alt-maleic anhydride)-block-poly(styrene) block copolymer with narrow molecular weight distributions were synthesized by nitroxide mediated radical polymerization (NMP) and the anhydride units were selectively converted to thiophene units. The thiophene decorated poly(styrene-alt-maleic anhydride) copolymer was emulsified in water, resulting in rod-like or cylindrical morphologies with diameters ≈ 90 nm while the non-decorated copolymers and thiophene decorated block copolymer resulted in spheres.

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Book Chapter on the use of Nitroxide Mediated Polymerization for Next Generation Materials is now Published!

Chapter 11: Novel Materials: From Nanoporous Materials to Micro-Electronics

From the book: Nitroxide Mediated Polymerization : From Fundamentals to Applications in Materials Science

Abstract: Nitroxide mediated polymerization (NMP) has been used to synthesize numerous different materials for a variety of emerging and next generation applications. NMP facilitates the incorporation of functional monomers, controls polymer microstructure and often does not require excessive purification steps prior to use in a variety of electronic and biological applications. This chapter discusses the role of NMP in the advancement of novel material applications, such as nanoporous membranes, nanofeatured templates, proton exchange membranes, and electron donor–acceptor polymers for organic photovoltaics, organic light emitting diodes and electrical memory applications. Finally, a short discussion on the current commercial implementations of NMP will also be presented.

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