Review in 2017

Antimicrobial cationic polymers mainly contain two functional components: the cationic groups and the hydrophobic groups. The antimicrobial activity is influenced by the type, amount, location and distribution of these two components. This review summarizes the structural designs of antimicrobial cationic polymers from primary to secondary structures, from covalent to noncovalent syntheses and from bulk to surface. It will provide some guidelines for developing molecular engineering of antimicrobial cationic polymers with tailor-made structures and functions.

In this review, we summarize the use of Diels–Alder reaction in the synthesis of arylene-based polymers, including polyphenylenes and ladder polymers, as well as graphene nanoribbons. These polymer materials are structurally related to each other, but rarely discussed all together in a same context. The importance and versatility of the Diels–Alder polymerization is highlighted for the synthesis of such polymers with various potential applications, for example, as polymer electrolyte membrane and organic semiconductors.

Synthesis and dynamic nature of macromolecular systems having mechanically linked polymer chains, which can undertake the topology transformation, are described. The rotaxane linking of polymer chains plays a crucial role in these systems. Successful syntheses of macromolecular [2]rotaxane (M2R) possessing single polymer axle and one crown ether wheel made possible the development of topology-transformable polymers from star to linear. Furthermore, rotaxane-linked ABC triblock copolymer and 4-arm and 6-arm star polymers were also synthesized and transformed to other topological polymers along with the property change.

The development of reversible-deactivation radical polymerization (RDRP) has made a great contribution not only to control of molecular weight and terminal structures but also to precise syntheses of copolymers. In particular, introducing a new concept into RDRP allows ‘sequence control’, which might lead to construction of ‘alphabet polymer’ bearing well-defined sequence like peptides in nature. Herein, some methodologies to realize sequence control based on RDRP are reviewed.

The design and functions of various liquid-crystalline (LC) polymers including main-chain, side-chain and network LC polymers as well as dendritic structures are described. These polymeric LC materials can be applied for electro-, ion-, photo-active materials as well as mechanically tough materials. The introduction of supramolecular design has also generated a new category of functional LC materials.

Incorporating additional electron donors or acceptors into conjugated D–A alternating polymers result in various conjugated D–A terpolymers. The presence of additional electron donors or acceptors can modulate their electronic absorptions, highest occupied molecular orbital/lowest unoccupied molecular orbital levels as well as interchain interactions and thin-film morphologies. Because of these structural features, conjugated D–A terpolymers have been intensively investigated for applications in field-effect transistors and photovoltaic cells. In this review, we introduce recent developments of conjugated D–A terpolymers with various combinations of electron donors and acceptors, and discuss the future perspectives of them.

Thermally stable and photosensitive polymers have been widely developed in recent years for their applications in the electronic packaging such as buffer coating, passivation layers, and insulation layers for redistribution in microelectronics due to their excellent thermal and reasonable dielectric properties. This review describes the recent progress of TSPSPs in the last decade and focuses on their design concept. After a brief introduction of the basic patterning procedure, various chemistries on the design of TSPSPs are highlighted along with two major patterning methodologies such as positive- and negative-working polymers. Furthermore, new applications of TSPSPs, such as low dielectric materials, high refractive index lenses, resists for ITO patterning, and π-conjugated polymers for organic-field effect transistors, are also introduced.

Both experimental measurements and molecular simulations were applied to probe the strain-induced crystallization (SIC) of natural rubber in real time, and some interesting results have been found. A very large fraction of unoriented amorphous phase remains, even at high strains. The onset strain of SIC in peroxide-cured NR decreases with increasing crosslinking density, while that in sulfur-cured NR is independent of crosslinking density. This difference may be caused by different network structures. Nanofillers, entanglements, non-rubber components and pseudoend-linked networks also result in abnormal SIC phenomena.