TY - JOUR
T1 - ROMP-Derived Pyridylborate Block Copolymers
T2 - Self-Assembly, pH-Responsive Properties, and Metal-Containing Nanostructures
AU - Pawar, Gajanan M.
AU - Lalancette, Roger A.
AU - Bonder, Edward M.
AU - Sheridan, John B.
AU - Jäkle, Frieder
N1 - Publisher Copyright:
© 2015 American Chemical Society.
PY - 2015/9/22
Y1 - 2015/9/22
N2 - The functionalization of organic polymers with polydentate ligands offers opportunities in areas ranging from supported catalysts to materials with desirable magnetic, redox-active, stimuli-responsive, and self-healing properties. Herein, we present the synthesis and self-assembly of tris(2-pyridyl)borate (Tpyb)-functionalized homo and block copolymers, prepared via ring-opening metathesis polymerization (ROMP) of (bicyclo[2.2.1]hept-5-en-2-yl)-4-phenyl) (pyridin-1-ium-2-yl)di(pyridin-2-yl)borate (M1) and dimethyl-7-oxabicyclo[2.2.1]hept-5-ene-exo,exo-2,3-dicarboxylate (M2) using Grubbs third-generation catalyst. Controlled polymerization was confirmed by gel permeation chromatography (GPC; also referred to as size exclusion chromatography, SEC) and multinuclear NMR spectroscopy. The solution self-assembly in block-selective solvents (MeOH, THF) was investigated by dynamic light scattering (DLS), scanning electron microscopy (SEM), scanning tunneling electron microscopy (STEM), and transmission electron microscopy (TEM), and the microphase separation in a thin film was imaged by atomic force microscopy (AFM). Hydrolysis of the ester-substituted oxanorbornene block with NaOH led to a new copolymer with carboxylate functionalities that can be dispersed in water. The latter displays multiresponsive properties as each of the individual blocks can be reversibly switched between hydrophobic and hydrophilic states by simple adjustment of pH. Cross-linking of the block copolymer aggregates via metal ion complexation was accomplished, and the feasibility of metal ion exchange was demonstrated by energy-dispersive X-ray spectroscopy (EDX).
AB - The functionalization of organic polymers with polydentate ligands offers opportunities in areas ranging from supported catalysts to materials with desirable magnetic, redox-active, stimuli-responsive, and self-healing properties. Herein, we present the synthesis and self-assembly of tris(2-pyridyl)borate (Tpyb)-functionalized homo and block copolymers, prepared via ring-opening metathesis polymerization (ROMP) of (bicyclo[2.2.1]hept-5-en-2-yl)-4-phenyl) (pyridin-1-ium-2-yl)di(pyridin-2-yl)borate (M1) and dimethyl-7-oxabicyclo[2.2.1]hept-5-ene-exo,exo-2,3-dicarboxylate (M2) using Grubbs third-generation catalyst. Controlled polymerization was confirmed by gel permeation chromatography (GPC; also referred to as size exclusion chromatography, SEC) and multinuclear NMR spectroscopy. The solution self-assembly in block-selective solvents (MeOH, THF) was investigated by dynamic light scattering (DLS), scanning electron microscopy (SEM), scanning tunneling electron microscopy (STEM), and transmission electron microscopy (TEM), and the microphase separation in a thin film was imaged by atomic force microscopy (AFM). Hydrolysis of the ester-substituted oxanorbornene block with NaOH led to a new copolymer with carboxylate functionalities that can be dispersed in water. The latter displays multiresponsive properties as each of the individual blocks can be reversibly switched between hydrophobic and hydrophilic states by simple adjustment of pH. Cross-linking of the block copolymer aggregates via metal ion complexation was accomplished, and the feasibility of metal ion exchange was demonstrated by energy-dispersive X-ray spectroscopy (EDX).
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U2 - 10.1021/acs.macromol.5b01216
DO - 10.1021/acs.macromol.5b01216
M3 - Article
AN - SCOPUS:84942288029
SN - 0024-9297
VL - 48
SP - 6508
EP - 6515
JO - Macromolecules
JF - Macromolecules
IS - 18
ER -