Development of temperature-responsive polymeric gels with physical crosslinking due to intermolecular 𝜋-𝜋 interactions.

Poly(N-isopropylacrylamide) PNIPAAm was polymerized with co-monomers containing a biphenyl moiety to create a unique thermoresponsive physically crosslinked system due to the presence of pi-pi interactions between the biphenyl moieties. The biphenyl monomers used were 2-phenylphenol monoacrylate (2PPMA) and 4-phenylphenol monoacrylate (4PPMA). These monomers were utilized to synthesize a set of polymers with biphenyl monomer (2PPMA/4PPMA) content from 2.

DEVELOPMENT OF BIPHENYL MONOMERS AND ASSOCIATED CROSSLINKED POLYMERS WITH INTRAMOLECULAR PI-PI INTERACTIONS.

Monomers containing biphenyl moieties were employed to create two sets of covalently crosslinked polymers that displayed noncovalent interactions in their 3-dimensional network. The biphenyls (precursors) used were 2-phenylphenol, 4-phenylphenol and 4,4'-dihydroxybiphenyl, and their acrylated forms were synthesized and named as 2-phenylphenolmonoacrylate (2PPMA), 4-phenylphenolmonoacrylate (4PPMA), and 4,4'-dihydroxybiphenyldiacrylate (44BDA), respectively. These were characterized by differential scanning calorimetry (DSC), nuclear magnetic resonance (NMR) and Fourier transform infrared spectroscopy (FTIR) to confirm the successful acrylation reaction.