Novel Water‐Soluble Poly(<i>m</i>‐benzamide)s: Precision Synthesis and Thermosensitivity in Aqueous Solution

Abstract

Abstract Summary: Chain‐growth polycondensations of 3‐aminobenzoic acid methyl esters 1a and 1b , bearing a tri‐ or tetra(ethylene glycol) methyl ether unit on the amino group, respectively, were carried out with lithium hexamethyldisilazide (LiHMDS) as a base and phenyl 4‐methylbenzoate ( 2 ) as an initiator in THF at 0 °C. The poly( m ‐benzamide)s obtained in the presence of N , N , N ′, N ′‐tetramethylethylenediamine (TMEDA) possessed narrow molecular weight distributions ( $\overline M _{\rm w} /\overline M _{\rm n}$ &lt; 1.2) with molecular weights that were determined by the feed ratios of [ 1 ] 0 /[ 2 ] 0 . Poly 1a and poly 1b were each soluble in water and exhibited a lower critical solution temperature (LCST) in water. Furthermore, the phase separation in water depended on the length of the oligo(ethylene glycol) side chain and on the molecular weight and molecular weight distribution of poly 1 . Thermally sensitive water‐soluble poly( m ‐benzamide)s. magnified image Thermally sensitive water‐soluble poly( m ‐benzamide)s.