Poly(hexamethylene biguanide) hydrochloride (PHMB)-based materials: synthesis, modification, properties, determination, and application

Abstract

As one of the major derivatives of biguanides, poly(hexamethylene biguanide) hydrochloride (PHMB) is a well-known commercially available polycationic antiseptic and disinfectant. PHMB is the hydrochloride salt of an amino polymer composed of an average of 12–16 biguanide groups separated by hydrophobic hexamethylene segments in the main chain. As a result, PHMB combines the advantageous characteristics of the biguanide group and polymeric polyelectrolyte. Currently, PHMB is regarded as a versatile biguanide-containing cationic polyelectrolyte, thus having a wide range of application prospects such as photoelectrical devices, gene delivery, clean coloration, CO₂ capture, and uranium recovery, as well as the well-accepted antimicrobial behavior. More interestingly, PHMB exhibits a remarkable ability to overcome charge screening limitations caused by inorganic salts when used for flocculating wastewater. Even though PHMB has been extensively reviewed in terms of its antimicrobial/antiviral activity and clinical applications over the past few decades, a comprehensive review on the synthesis, modification strategies, quantitative determination, and applications of PHMB in recent years is still lacking. Herein, we for the first time present a timely review to give a panoramic view of PHMB covering these aspects. The review article presented here may shed light on a more rational exploration of PHMB-based materials for various applications.