Membranes have an increasingly important role in alleviating water scarcity and the pollution of aquatic environments. Promising molecular-level design approaches are reviewed for membrane materials, focusing on how these materials address the urgent requirements of water treatment applications.

Materials for next-generation desalination and water purification membranes

The attachment strategy based on catecholic chemistry has been arousing renewed interest since the work on polymerized catecholic amine (polydopamine) (Messersmith et al., Science, 2007, 318, 426) was published. Catechols and their derived compounds can self-assemble on various inorganic and organic materials, including noble metals, metals, metal oxides, mica, silica, ceramics and even polymers. It opens a new route to the modification of various substrates and the preparation of functional composite materials by simple chemistry. However, there is still not a full review so far about the attachment chemistry despite the dramatically increasing number of publications. This critical review describes the state-of-the-art research in the area: the design and synthesis of catecholic molecules, their adsorption mechanisms and the stability of assemblies in solution, and their applications etc. Some perspectives on future development are raised (195 references).

Bioinspired catecholic chemistry for surface modification.

3.10 - Nitroxide-Mediated Polymerization

This Perspective presents recent advances in macromolecular engineering enabled by ATRP. They include the fundamental mechanistic and synthetic features of ATRP with emphasis on various catalytic/initiation systems that use parts-per-million concentrations of Cu catalysts and can be run in environmentally friendly media, e.g., water. The roles of the major components of ATRP—monomers, initiators, catalysts, and various additives—are explained, and their reactivity and structure are correlated. The effects of media and external stimuli on polymerization rates and control are presented. Some examples of precisely controlled elements of macromolecular architecture, such as chain uniformity, composition, topology, and functionality, are discussed. Syntheses of polymers with complex architecture, various hybrids, and bioconjugates are illustrated. Examples of current and forthcoming applications of ATRP are covered. Future challenges and perspectives for macromolecular engineering by ATRP are discussed.

Macromolecular Engineering by Atom Transfer Radical Polymerization

The use of light to mediate controlled radical polymerization has emerged as a powerful strategy for rational polymer synthesis and advanced materials fabrication. This review provides a comprehensive survey of photocontrolled, living radical polymerizations (photo-CRPs). From the perspective of mechanism, all known photo-CRPs are divided into either (1) intramolecular photochemical processes or (2) photoredox processes. Within these mechanistic regimes, a large number of methods are summarized and further classified into subcategories based on the specific reagents, catalysts, etc., involved. To provide a clear understanding of each subcategory, reaction mechanisms are discussed. In addition, applications of photo-CRP reported so far, which include surface fabrication, particle preparation, photoresponsive gel design, and continuous flow technology, are summarized. We hope this review will not only provide informative knowledge to researchers in this field but also stimulate new ideas and applications to further advance photocontrolled reactions.

http://pubs.acs.org/doi/pdf/10.1021/acs.chemrev.5b00671

Light-Controlled Radical Polymerization: Mechanisms, Methods, and Applications

Keywords: Fragmentation Chain-Transfer ; Self-Assembled Monolayers ; Walled Carbon Nanotubes ; Well-Defined Polymer ; Nitroxide-Mediated Polymerization ; Block-Copolymer Brushes ; Poly(Methyl Methacrylate) Brushes ; Transfer Raft Polymerization ; Quartz-Crystal Microbalance ; Poly(Acrylic Acid) Brushes Reference EPFL-REVIEW-148464doi:10.1021/cr900045aView record in Web of Science Record created on 2010-04-23, modified on 2017-05-10

Polymer Brushes via Surface-Initiated Controlled Radical Polymerization: Synthesis, Characterization, Properties, and Applications

Polymer Brushes via Surface‐Initiated Controlled Radical Polymerization: Synthesis, Characterization, Properties, and Applications

This manuscript reports a facile strategy for the modification of polyethylene, a widely used biomaterial, with a thin non-biofouling coating that can act as a platform to introduce biochemical cues to control and direct, e.g., cell adhesion and proliferation. The non-biofouling coating is produced, following a two-step strategy involving photobromination of the polyethylene substrate followed by surface-initiated ATRP of poly(ethylene glycol) methacrylate. The resulting coatings, which are referred to as polymer brushes, are robust and withstand prolonged exposure to aqueous ethanol and phosphate buffered saline and also do not show any signs of detachment or degradation in the in vivo studies over a period of 10 d. Functionalization of these polymer brush coatings with extracellular matrix derived peptide sequences, promotes adhesion and spreading of endothelial cells.

A facile strategy for the modification of polyethylene substrates with non-fouling, bioactive poly(poly(ethylene glycol) methacrylate) brushes

In this Article, we studied the surface immobilization of five organic-acid-modified atom-transfer radical polymerization (ATRP) initiators based on salicylic acid, catechol, phthalic acid, and m- and p-benzoic acid on alumina, and we also investigated the growth of hydrophilic poly(2-hydroxyethyl methacrylate) (PHEMA) and poly(poly(ethylene glycol)methycrylate) (PPEGMA6) brushes from the resulting initiator-modified substrates. Whereas the surface immobilization of phthalic acid- and benzoic acid-based initiators results in only very thin brushes or no brush growth at all, SI-ATRP of HEMA and PEGMA6 from alumina surfaces modified with salicylate or catechol generates brushes with thicknesses comparable to those obtained using organosilane-based initiators. Most interestingly, the surface immobilization of the catechol- and salicylate based-initiators was found to be pH-dependent, which allowed facile variation of the ATRP initiator surface concentration and, concomitantly, the polymer brush grafting dens...

Aqueous fabrication of pH-gated, polymer-brush-modified alumina hybrid membranes.

There is provided a selectively permeable biointerface membrane, permitting selective diffusion of analyte therethrough, for use in an analyte sensor comprising a nanoporous substrate and a coating, on the nanoporous substrate, comprising a plurality of polymer chains whereby each polymer chain is attached at one chain end thereof to a surface of the nanoporous substrate. There are also provided methods for the preparation of the selectively permeable membrane and an analyte sensor comprising the membrane.

Laurent Lavanant

Papers

Polymer Brushes via Surface-Initiated Controlled Radical Polymerization: Synthesis, Characterization, Properties, and Applications

Polymer Brushes via Surface‐Initiated Controlled Radical Polymerization: Synthesis, Characterization, Properties, and Applications

A facile strategy for the modification of polyethylene substrates with non-fouling, bioactive poly(poly(ethylene glycol) methacrylate) brushes

Aqueous fabrication of pH-gated, polymer-brush-modified alumina hybrid membranes.

Selectively permeable coated membrane