Phase Behavior of Complementary Multiply Hydrogen Bonded End-Functional Polymer Blends

Abstract

Blends of diamidonaphthyridine (Napy) end-functional poly(n-butyl acrylate) (PnBA) and ureidopyrimidinone (UPy) end-functional poly(benzyl methacrylate) (PbnMA) were studied as a function of the component molecular weights to compare with prior theoretical predictions.1 Macroscopic phase separation was observed to be prevented by the reversible association of end-functional polymers to form supramolecular diblock copolymers, resulting in stabilization of the interface between the polymers. At low molecular weights homogeneous microstructures were observed, in contrast to nonfunctional homopolymer blends of the same molecular lengths, which rapidly phase separate over macroscopic length scales. At higher molecular weights, the blend structure was reminiscent of compatibilized homopolymer blends, with the phase-separated domain size rapidly increasing with temperature. To compare with theoretical phase diagrams, the temperature-dependent Flory-Huggins χ parameter was measured, and it was found that PnBA/PbnMA covalent diblock copolymers show unusual lower critical ordering (LCOT) behavior with χ slightly increasing with temperature (χ(T) = 0.036 -0.56/T).

Spacer‐length‐dependent association in polymers with multiple‐hydrogen‐bonded end groups

“…[1][2][3][4] Theoretical work has shown that the domain size and morphology of the phase-separated structures critically depend on the strength of the interpolymer noncovalent interactions. [5][6][7][8][9][10] To achieve these attractive enthalpic interpolymer interactions, end-functionalized homopolymers have been prepared with functional groups capable of noncovalent assembly such as hydrogen bonding, [11][12][13][14][15][16][17][18][19][20] ionic, 21 transition-metal, 22,23 host-guest, [24][25][26] and fluorophilic 27 interactions. Typically, these functional groups are attached to a homopolymer via a short, aliphatic spacer.…”

“…KEYWORDS: atom transfer radical polymerization (ATRP); diffusion-ordered spectroscopy; hydrogen bonding; supramolecular diblock copolymers INTRODUCTION The combination of supramolecular chemistry and the controlled phase separation of diblock copolymers can result in a wealth of nanoscale morphologies with applications ranging from semiconductor integrated circuit design to the development of subnanometer porous films for separation processes. [1][2][3][4] Theoretical work has shown that the domain size and morphology of the phase-separated structures critically depend on the strength of the interpolymer noncovalent interactions.5-10 To achieve these attractive enthalpic interpolymer interactions, end-functionalized homopolymers have been prepared with functional groups capable of noncovalent assembly such as hydrogen bonding, [11][12][13][14][15][16][17][18][19][20] ionic, 21 transition-metal, 22,23 host-guest, 24-26 and fluorophilic 27 interactions. Typically, these functional groups are attached to a homopolymer via a short, aliphatic spacer.…”

“…5-10 To achieve these attractive enthalpic interpolymer interactions, end-functionalized homopolymers have been prepared with functional groups capable of noncovalent assembly such as hydrogen bonding, [11][12][13][14][15][16][17][18][19][20] ionic, 21 transition-metal, 22,23 host-guest, 24-26 and fluorophilic 27 interactions. Typically, these functional groups are attached to a homopolymer via a short, aliphatic spacer.…”

Intrinsic Self-Healing Polymers Based on Supramolecular Interactions: State of the Art and Future Directions

“…By investigating 2,7-diamido-1,8-naphthyridine (DAN) and UPy end-functionalized PnBAs and poly(benzyl methacrylate)s it was found that the phase behavior and microstructure in the bulk were controlled by hydrogen bonding interactions [100] as well as by temperature changes, directly influencing the compatibility of the phases [101]. Thus, UPy dimerization led to compatibilization, whereas complementary hydrogen bonding interactions resulted in significant reduction in macroscopic phase separation [100] and in the formation of supramolecular diblock copolymers [101] or graft polymers [102].…”

“…Thus, UPy dimerization led to compatibilization, whereas complementary hydrogen bonding interactions resulted in significant reduction in macroscopic phase separation [100] and in the formation of supramolecular diblock copolymers [101] or graft polymers [102]. Supramolecular alternating copolymers were formed by hydrogen bonding interactions between a 1:1 mixture of a bis-UPy-functionalized polyTHF and a bis-DAN-functionalized low molar mass linker [103].…”