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Main-chain chiral quaternary ammonium polymers were successfully synthesized by the quaternization polymerization of cinchonidine dimer with dihalides. The polymerization occurred smoothly under optimized conditions to give novel type of main-chain chiral quaternary ammonium polymers. The catalytic activity of the polymeric chiral organocatalysts was investigated on the asymmetric benzylation of N-(diphenylmethylidene)glycine tert-butyl ester.

This chapter contains sections titled: Introduction Synthetic Methods Leading to Ferrocene‐Containing Polymers Synthesis of Side‐Chain Ferrocene‐Containing Polymers (type B) Synthesis of Main‐Chain Ferrocene‐Containing Polymers Properties of Ferrocene‐Containing Polymers Ferrocene‐Containing Dendrimers Conclusions and Outlook References

Amphiphilic statistical copolymers are valuable synthetic macromolecules for the formation of small, well-defined nanoassemblies able to be utilized as nanocarriers for drug and/or gene delivery applications. In this work, the synthesis of amphiphilic linear statistical copolymers of the poly(benzyl methacrylate-co-dimethylaminoethyl methacrylate) [P(BzMA-co-DMAEMA)] type is described in three different comonomer compositions. Their synthesis was realized through a one-pot reversible addition-fragmentation chain transfer (RAFT) solution polymerization scheme. Further quaternization of the amine groups of DMAEMA with methyl iodide (CH3I) resulted in cationic amphiphilic statistical copolymers. Macromolecular characterization was performed using size exclusion chromatography (SEC) and spectroscopic techniques (1H-NMR and ATR-FTIR). The aggregation properties of the copolymers in aqueous media were studied via dynamic light scattering (DLS) and electrophoretic light scattering (ELS). Bimodal size distributions were determined in some cases. The BzMA to DMAEMA ratio determined aggregate size, with the copolymer of lower hydrophobic BzMA content producing smaller nanoparticles. Cryogenic transmission electron microscopy (cryo-TEM) showed the presence of spherical assemblies resulting from aggregation of primary micelles in the case of higher BzMA content. The copolymer aggregates experience dissociation at high salt concentration, and the pH-responsiveness of the amine precursors results in the formation of multifunctional potential nanocarriers.

In this work, the antimicrobial action of partially quaternized poly(2-(dimethylamino)ethyl methacrylate) (PQDMAEMA) copolymers using different alkyl halides is presented. The poly(2-(dimethylamino)ethyl methacrylate) (PDMAEMA) homopolymer was synthesized by group transfer polymerization, followed by the modification of its tertiary amine groups, using bromoethane, iodoethane, bromohexane and bromoethanol, to introduce permanent cationic, quaternary ammonium salt moieties, randomly distributed along the polymer chains. In all cases, the degree of quaternization was low, at ~10 mol%, as verified by proton nuclear magnetic resonance spectroscopy to preserve the thermo-responsive character of the PDMAEMA precursor polymer. The biocidal activity of the lightly quaternized PQDMAEMA copolymers against Escherichia coli and Staphylococcus aureus was evaluated by calculating the minimum inhibitory concentration (MIC) as well as the minimum bactericidal concentration (MBC) of the polymers and by comparing them to the respective values of the precursor non-quaternized PDMAEMA homopolymer. The antibacterial mechanism of action in the solution was studied by zeta potential measurements, scanning electron microscopy and protein leakage tests signifying the disruption of the outer membrane of the bacterial cells to release their periplasmic proteins.

In this work, the synthesis and the stimuli-responsive self-assembly behavior of novel double-hydrophilic poly(2-(dimethylamino)ethyl methacrylate-co-(oligo ethylene glycol)methacrylate) random copolymers and their chemically modified derivatives are presented. The synthesis of P(DMAEMA-co-OEGMA) copolymers of different DMAEMA mass compositions was successfully conducted through RAFT polymerization, further followed by the hydrophilic/hydrophobic quaternization with methyl iodide (CH3I), 1-iodohexane (C6H13I), and 1-iodododecane (C12H25I). The tertiary and quaternary amines are randomly arranged within the DMAEMA segment, responding thus to pH, temperature, and salt alterations in aqueous solutions. Light scattering techniques elucidated the intramolecular self-folding and intermolecular self-assembly of polymer chains of P(DMAEMA-co-OEGMA) copolymers upon exposure to different pHs and temperatures. Q(P(DMAEMA-co-OEGMA)) cationic polyelectrolytes demonstrated moderate response to pH, temperature, and ionic strength as a result of the permanent hydrophilic/hydrophobic profile, closely connected with the attached alkyl chains and the quaternization degree. Moreover, fluorescence spectroscopy measurements confirmed the internal micropolarity and the picture of the aggregate inner structure.

Graft polymerization-quaternization double modification has become a new effective method for preparing antibacterial chitosan (CS) in recent years. To improve the properties of double modified CS, the effects of molecular structures of amino-containing acrylate (ACA) monomer grafted onto CS (CS- g -PACA) and a quaternary ammonium reagent used for the quaternization of CS- g -PACA have been investigated in the study. A series of ACA monomers, i.e., dimethylaminoethyl methacrylate (DMAEMA), diethylaminoethyl methacrylate (DEAEMA) and 2-( tert -butyl amino)ethyl methacrylate (TBAEMA), were firstly grafted onto the molecular chain of CS. Then, CS- g -PACA was quaternized by various quaternary ammonium reagents, i.e., three kinds of chloralkane include 1-chlorobutane, 1-chlorooctane and 1-chlorododecane. The modified CS was blended with PVA to prepare nanofiber membranes by electrospinning. The major functional properties of the nanofiber membranes, e.g., fiber morphology, thermal stability, tensile property, water stability, and inhibition of E.coli and S.aureus as representatives of gram negative and positive bacterial, were evaluated systematically. The results showed that when ACA and chloralkane were TBAEMA and 1-chlorobutane, respectively, the graft-quaternization double modified CS/PVA blend nanofiber membrane possessed a more uniform and smooth fiber structure, higher thermal stability, tensile strength, water stability, and better inhibition function to the bacteria. For instance, the diameter of the fiber could reach ~ 180 nm and tensile strength of the fiber membrane could touch the value of 20.1 MPa as well. The inhibition rate of E.coli and S.aureus was as high as 95.9% and 99.6%, respectively. Double modified CS nanofibers have shown great potential to be used as biocompatible and environment-friendly medical and hygiene textiles. Graphical abstract

In this study, the use of anionic polymerization for the synthesis of living poly(dimethylsiloxane) or PDMS-Li+, as well as poly(2-vinylpyridine) or P2VP-Li+ homopolymers, and the subsequent use of chlorosilane chemistry in order for the two blocks to be covalently joined leading to PDMS-b-P2VP copolymers is proposed. High vacuum manipulations enabled the synthesis of well-defined materials with different molecular weights (Μ¯n, from 9.8 to 36.0 kg/mol) and volume fraction ratios (φ, from 0.15 to 0.67). The Μ¯n values, dispersity indices, and composition were determined through membrane/vapor pressure osmometry (MO/VPO), size exclusion chromatography (SEC), and proton nuclear magnetic resonance spectroscopy (1H NMR), respectively, while the thermal transitions were determined via differential scanning calorimetry (DSC). The morphological characterization results suggested that for common composition ratios, lamellar, cylindrical, and spherical phases with domain periodicities ranging from approximately 15 to 39 nm are formed. A post-polymerization chemical modification reaction to quaternize the nitrogen atom in some of the P2VP monomeric units in the copolymer with the highest P2VP content, and the additional characterizations through 1H NMR, infrared spectroscopy, DSC, and contact angle are reported. The synthesis, characterization, and quaternization of the copolymer structure are important findings toward the preparation of functional materials with enhanced properties suitable for various nanotechnology applications.

Radical polymerization reactions were employed to synthesize poly(2-acrylamido-2-methyl-1-propanesulfonic acid -co-1-vinylimidazole), hydrogels at neutral and acidic reaction conditions. The results of Fourier Transform Infrared (FT-IR) spectroscopy and scanning electron microscopy spectroscopy confirmed the chemical composition of the synthesized hydrogels. Loading Ag into hydrogels, removing loosely-bound Ag ions, and reducing Ag ions with sodium borohydride (NaBH4) were used to construct p(AMPS-Na+-co-VIm)-Ag and p(AMPS-H+-co-VIm)-Ag. Metal nanoparticles embedded p(AMPS-Na+-co-VIm)-Ag and p(AMPS-H+-co-VIm)-Ag were visualized by high resolution X-ray photoelectron spectroscopy, transmission electron microscopy and energy dispersive X-ray. FT-IR spectroscopy and HR-XPS demonstrated that the interaction of network heteroatoms with Ag nanoparticles was responsible for stabilizing silver nanoparticles. Atomic absorption spectroscopy was also employed to measure the concentrations of metals in all compounds. P(AMPS-Na+-co-VIm)-Ag and p(AMPS-H+-co-VIm)-Ag composites were used as catalyst in the oxidation of alcohols by emphasizing the effects of different parameters such as oxidant, substituent effect, etc. The prepared porous hydrogels and related composites were also utilized in the adsorption of Benzyl alcohol from aqueous solutions. P(AMPS-Na+-co-VIm) and its composite has better performance than p(AMPS-H+-co-VIm) and p(AMPS-H+-co-VIm)-Ag. Because, absorption capacity is increased with an increase in the high porosity and it is depending on porous size and shapes. In continue, quaterniztion effect by 1,4-dibromobutane on catalytic performance of nano-composites was investigated. The results confirmed the easy separation of the prepared catalysts from the reaction media. Moreover, the catalysts could efficiently be recycled four times without losing their quality. It was also proved that the catalysts were recyclable, durable, and leaching-resistant.

Stimuli-responsive copolymers are of great interest for targeted drug delivery. This study reports on a controllable post-polymerization quaternization with 2-bromomethyl-4-fluorophenylboronic acid of the poly(4-vinyl pyridine) (P4VP) block of a common poly(styrene)-b-poly(4-vinyl pyridine)-b-poly(ethylene oxide) (SVE) triblock terpolymer in order to achieve a selective responsivity to various diols. For this purpose, a reproducible method was established for P4VP block quaternization at a defined ratio, confirming the reaction yield by 11B, 1H NMR. Then, a reproducible self-assembly protocol is designed for preparing stable micelles from functionalized stimuli-responsive triblock terpolymers, which are characterized by light scattering and by cryogenic transmission electron microscopy. In addition, UV-Vis spectroscopy is used to monitor the boron-ester bonding and hydrolysis with alizarin as a model drug and to study encapsulation and release of this drug, induced by sensing with three geminal diols: fructose, galactose and ascorbic acid. The obtained results show that only the latter, with the vicinal diol group on sp2-hybridized carbons, was efficient for alizarin release. Therefore, the post-polymerization method for triblock terpolymer functionalization presented in this study allows for preparation of specific stimuli-responsive systems with a high potential for targeted drug delivery, especially for cancer treatment.

In this work, the synthesis and the aqueous solution self-assembly behavior of novel partially hydrophobically modified poly(2-(dimethylamino) ethyl methacrylate)-b-poly(oligo(ethylelene glycol) methyl ether methacrylatetabel) pH and temperature responsive random diblock copolymers (P(DMAEMA-co-Q6/12DMAEMA)-b-POEGMA), are reported. The chemical modifications were accomplished via quaternization with 1-iodohexane (Q6) and 1-iodododecane (Q12) and confirmed by 1H-NMR spectroscopy. The successful synthesis of PDMAEMA-b-POEGMA precursor block copolymers was conducted by RAFT polymerization. The partial chemical modification of the diblocks resulted in the permanent attachment of long alkyl chains on the amine groups of the PDMAEMA block and the presence of tertiary and quaternary amines randomly distributed within the PDMAEMA block. Light scattering techniques confirmed that the increased hydrophobic character results in the formation of nanoaggregates of high mass and tunable pH and temperature response. The characteristics of the aggregates are also affected by the aqueous solution preparation protocol, the nature of the quaternizing agent and the quaternization degree. The incorporation of long alkyl chains allowed the encapsulation of indomethacin within the amphiphilic diblock copolymer aggregates. Nanostructures of increased size were detected due to the encapsulation of indomethacin into the interior of the hydrophobic domains. Drug release studies demonstrated that almost 50% of the encapsulated drug can be released on demand by aid of ultrasonication.