Surface-Initiated Ring-Opening Metathesis Polymerization (SI-ROMP): History, General Features, and Applications in Surface Engineering with Polymer Brushes

Abstract

Surface-Initiated Ring-Opening Metathesis Polymerization (SI-ROMP) has attracted great attention in the past two decades because of its high efficiency in decorating material surfaces with functional polymer brushes. To fill the vacancy of review articles in SI-ROMP, this article is aimed at giving an overview of the history, the general features and procedures, and applications of SI-ROMP, guiding future researchers in this field. In general, SI-ROMP consists of three main steps: surface functionalization with olefin anchors, attachment of catalyst to the surface, and polymerization from the surface. Several metal-based catalysts for ROMP in solution have been developed, but most SI-ROMP reactions use the ruthenium-based Grubbs catalysts. SI-ROMP enables the rapid growth of polymer films on a large variety of substrates such as silica, gold, graphene oxides, carbon nanotubes, metal oxide nanowires, and composite polymer membranes. There are many methods to characterize these polymer brushes. In addition, some novel techniques have been developed to precisely control the surface polymer growth and lead to polymer films with unique structures and functions. Up to this day, SI-ROMP can be applied to the surface engineering of many novel materials, including ultrahydrophobic surfaces, microfluidic channels, electric devices, ion exchange media, and responsive surfaces.

Synthesis of Bottlebrush Copolymers Using a Polypseudorotaxane Intermediate

“…Accordingly, the complexation could include other known host–guest pseudorotaxanes, for example, cyclodextrin-admantyl (and other hydrophobic guests), ,,,,, pillararene-aliphatic chains, aromatics, − and so on; note that these would produce systems without ionic charges. Finally, the brushes could be constructed using other approaches, for example, atom transfer radical polymerization, ,,,,,− reversible addition-fragmentation chain transfer polymerization (RAFT), ,,,− ring-opening polymerization (ROP), including ring-opening metathesis polymerization ,,,− and so on. Therefore, we believe that this approach represents a new, useful, and flexible paradigm for the synthesis of bottlebrush polymers.…”

“…In recent years, there has also been great interest in “bottlebrush polymers,” polymers which possess densely positioned long side chains; − this field started with studies of polymers attached to surfaces, so-called “polymer brushes.” With regard to the present work, we reported the first pseudorotaxane graft copolymer by self-assembly of a bis­( m -phenylene)-32-crown-10-based polyester and a complementary viologen-terminated polystyrene guest . Takata et al , and others − have also demonstrated formation of graft polymers by supramolecular host–guest complexations.…”

Surface Chain-Transfer Ring-Opening Metathesis Polymerization

“…Surface-initiated polymerization (SIP) has been widely used for surface modification because it affords high graft density, − controllable graft thickness, − well-tuned surface characteristics, , and the possibility of secondary polymerization. , Among various types of SIP methods, surface-initiated ring-opening metathesis polymerization (SI-ROMP), first reported in 1999 by Weck et al, allows for the grafting of olefinic backbones to the surface and attracts great research attention. Different types of ROMP monomers including norbornenes, , cyclooctenes, , cyclooctadienes, , cyclopentenes, , as well as macromonomers with norbornenes end-groups, , are used for surface modification via SI-ROMP. Linear, branched, and bottlebrush polymers are grafted to substrates like gold nanoparticles, clays, silica nanoparticles, silica wafers, etc., to afford unique surface structures and properties. ,− …”

“…In general, a typical SI-ROMP protocol contains three essential procedures, as demonstrated in Scheme a: (i) olefin groups are grafted to the surface covalently or noncovalently; (ii) metathesis catalysts are attached on the surface by reacting with the olefin bonds; (iii) monomers are grafted from the surface via ROMP. ,, Due to the living nature of ROMP mechanism, SI-ROMP is a living surface polymerization and can provide well controlled grafted chain with narrow polydispersity. ,− …”

Hydrophobic and antifouling modification of graphene oxide with functionalized polynorbornene by surface-initiated ring-opening metathesis polymerization

“…Compared with ROMP reacting in the solution phase, SI-ROMP has unique features in terms of experimental procedures, kinetics of the polymer growth, and side-reactions. 29 In general,…”