Size controllable synthesis and antimicrobial activity of poly-N,N′-[(4,5-dihydroxy-1,2-phenylene)bis(methylene)]bisacrylamide microspheres

The monomer N,N′-[(4,5-dihydroxy-1,2-phenylene)bis(methylene)]bisacrylamide (OHABA) was successfully synthesized by the Friedel-Crafts reaction. Using precipitation polymerization, POHABA microspheres were easily obtained in a size-controlled manner. The microsphere diameters were controlled by the dosage of initiator (2,2′-azobisisobutyronitrile, AIBN). The minimum and maximum microsphere size are 0.83 ± 0.07 μm and 1.98 ± 0.13 μm, respectively. Antimicrobial activity test results showed that both OHABA and POHABA microspheres had a broad-spectrum inhibitory effect on both Gram-positive and Gram-negative bacteria, but POHABA performed better than the OHABA monomer. The inhibition rate of larger (1.98 μm in diameter) and smaller (1.00 μm in diameter) POHABA microspheres at the concentration of 0.238 mg mL^-1 were 74.3% and 37.0% for soil microorganisms after a 48 hour reaction, respectively.