In this work, poly(glycidyl methacrylate) (PGMA, G) homopolymers with different molecular weights (5600-21,000 gmol(-1)) were synthesized by atom transfer radical polymerization (ATRP) method. Epoxy groups of PGMA homopolymers were converted to hydroxyl and 1-methyl piperazin residues by reacting with 1-methyl piperazine via ring-opening reaction. The obtained poly(2-hydroxy-3-methyl piperazinepropyl methacrylate) (PHMPPMA, G-P) homopolymers (from 9450 to 35,900 gmol(-1)) were reacted with alkyl halides of different carbon chain lengths (methyl-, ethyl-, propyl-, butyl-, pentyl-iodides, hexyl bromide) and benzyl chloride (arylhalide) to form quaternary PHMPPMA homopolymers (G-QP). MIC values varied from 0.125 mg/ml to 5 mg/ml. It was found that homopolymer (1G-6QP) produced by the modification of PHMPPMA with hexyl iodide with low molecular weight had highest quorum-sensing inhibition zone ranging from 14.5 +/- 0.5 mm (MIC) and 10.0 +/- 0.5 mm (MIC/4) as well as best violacein inhibition 61.0 +/- 2.2% (MIC) to 17.3 +/- 0.6% (MIC/8). Homopolymer (1G-BzQP) produced by the modification of PHMPPMA with benzyl chloride with the lowest molecular weight had best biofilm inhibition ranging from 77.83 +/- 1.60% (MIC) to 18.23 +/- 0.87% (MIC/8) on S. aureus, 75.70 +/- 5.20% (MIC) to 14.25 +/- 1.10% (MIC/8) on E. coli and from 86.16 +/- 0.83% (MIC) to 12.41 +/- 0.76% (MIC/8) on C. albicans. The synthesized homopolymers can be used to combat microbial resistance and severity of infections.