Quaternary Ammonium Salts-Based Materials: A Review on Environmental Toxicity, Anti-Fouling Mechanisms and Applications in Marine and Water Treatment Industries

Abstract

The adherence of pathogenic microorganisms to surfaces and their association to form antibiotic-resistant biofilms threatens public health and affects several industrial sectors with significant economic losses. For this reason, the medical, pharmaceutical and materials science communities are exploring more effective anti-fouling approaches. This review focuses on the anti-fouling properties, structure-activity relationships and environmental toxicity of quaternary ammonium salts (QAS) and, as a subclass, ionic liquid compounds. Greener alternatives such as QAS-based antimicrobial polymers with biocide release, non-fouling (i.e., PEG, zwitterions), fouling release (i.e., poly(dimethylsiloxanes), fluorocarbon) and contact killing properties are highlighted. We also report on dual-functional polymers and stimuli-responsive materials. Given the economic and environmental impacts of biofilms in submerged surfaces, we emphasize the importance of less explored QAS-based anti-fouling approaches in the marine industry and in developing efficient membranes for water treatment systems.

Keywords: anti-biofouling materials; environmental toxicity; ionic liquids (ILs); marine anti-fouling systems; quaternary ammonium salts (QASs).

Figure 2

General structure of QASs (a) and commercial QAS-based disinfectants (b) [23].

Figure 4

(a) Antibacterial polyvinyl alcohol formaldehyde (PVF) polymer. Adapted from [72]; (b,c) Polyurethane polymers grafted with quaternary ammonium groups. Adapted from [77,78].

Figure 5

(a) Antibacterial polysiloxane polymers with imidazolium salts. Adapted from [86]. (b) Quaternary ammonium-functionalized POSS as an antimicrobial additive for polysiloxane coatings. Adapted from [89]. (c) 1,2,3-triazolium-functionalized POSS additive for dental restorative system. Adapted from [90].

Figure 7

Representative examples of dual-functional polymeric materials. (a) Polyurethane with a contact-active antibacterial upper-layer and anti-fouling bacterial repellent sub-layer. Adapted from [103]. PVA (b) and chitosan polymers (c) modified with biocidal QASs and non-fouling/biocompatible zwitterionic group. Adapted from [63,104] (d) Amphiphilic cationic polymer with enhanced biocompatibility. Adapted from [107]. (e) Tri-block copolymer with anti-fouling and bactericide units. Adapted from [108].

Figure 10

QAS-based materials for water treatment. (a) Cellulose acetate membrane covalently modified with QASs. Adapted from [135]. (b) PVDF membrane modified with QASs by silica nanoparticles interlayer. Adapted from [136]. (c) Assembly of aromatic quaternary ammonium compound (piQAs) with graphene hydrogel (rGO). Adapted from [138].

Figure 1

Schematic illustration of anti-biofouling strategies.

Figure 3

Bio-based polymers with QASs groups and reversible schiff-base crosslinking to guarantee self-healing properties (a,b). Adapted from [60,61]; (c) Hydroxypropyltrimethyl ammonium chloride chitosan (HACC) a biocompatible material in the orthopedic field.

Figure 6

(a,b) Crosslinked matrix with diffusive and covalently attached biocide moieties. Adapted from [93,94].

Figure 8

Representative examples of stimuli-responsive polymeric materials. (a) Cellulosic materials with antibacterial activity explicated by quaternary ammonium moiety and photosensitizers mediated ROS response. Adapted from [114]. (b) Polymeric platform with antibacterial activity explicated by lysine-QASs and polydopamine with photothermal properties. Adapted from [107]. (c) Cross-linked and pH-responsive hydrogel constituted of quaternized chitosan (HTCC) and oxidized dextran/dopamine adduct. Adapted from [115].

Figure 9

Representative examples of switchable materials. (a) Photo-responsive poly[2-((4,5-dimethoxy-2-nitrobenzyl)oxy)-N-(2-(methacryloyloxy)ethyl)-N,N-dimethyl-2-ox-oethan-1-aminium] (PolyCBNA) hydrogel switching from its cationic antimicrobial to zwitterionic anti-fouling form. Adapted from [119]. (b) Acid-sensitive multilayer with reversible charge’s surface and switchable bactericidal and bacteria-repelling functions. Adapted from [120].

Figure 11

Schematic diagram of the marine biofouling process.

Figure 12

(a) Non-toxic anti-macrofouling alkyl imidazolium ILs. Adapted from [155]. (b) Imidazolium quaternized POSS adsorbed on the surface of biologically active oxides to generate an efficient anti-fouling system. Adapted from [87]. (c) Acrylate matrix incorporating the biocide releasing homopolymer PSSAmC16. Adapted from [156]. (d) Biocide quaternary ammonium “tannate” as an antimicrobial paint additive. Adapted from [157].

Figure 13

PHDMS–PDMS crosslinked polymer with pendant quaternary ammonium groups. Adapted from [159].

Figure 14

Anti-fouling approaches with silica nanoparticles. (a) Self-polishing acrylate polymer conjugated with antibacterial QAS-based silica nanoparticles. Adapted from [174]. (b) Mesoporous silica nanoparticles modified with contact-killing QASs and loaded with the biocide Parmetol S15. Adapted from [175,176].

Figure 15

Antimicrobial materials for aquaculture nets. (a) Cross-linked antimicrobial polymer with releasable and contact-killing QASs. Adapted from [178]. (b) Multilayer coating with antibacterial and non-fouling polymers. Adapted from [179].

Figure 16

Anti-biofouling coating for marine sensors based on dual-functionalized magnetic composite. Adapted from [181].