Reviews & Analysis

In this review, we highlight recent advances in polymeric hybrid nanocarriers for photothermal treatment of cancer. These polymeric hybrid nanocarriers can store and deliver NIR-absorbing agents to cancer cells and tumor sites, exhibiting significant cytotoxic effects upon treatment under external light irradiation. Possible challenges and future prospects in this field are also emphasized.

Glycosaminoglycans (GAGs) are one of the most important polysaccharide in the living systems. However, preparation of GAGs is difficult owing to the complex structure and high molecular weight. In order to obtain the GAGs’ materials with a practical way, we investigated a new approach to mimic GAGs using polymer chemistry. We reviewed the syntheses of GAGs of the previous reports and the glycopolymers having GAGs moieties, including our GAGs' mimic polymers.

This review summarizes the most widely used mechanisms in high-performance polymeric resistive memory devices, such as charge transfer, space charge trapping and filament conduction. In addition, recent studies of functional high-performance polymers for memory device applications are reviewed, compared and differentiated based on the mechanisms and structural design methods used. The reported memory properties show extremely high endurance during long-term operation, making high-performance polymers very suitable materials for memory applications.

Recent developments on bipolar electrochemistry as an effective tool for the fabrication of gradient polymer surfaces were reviewed. The electrochemical doping and reactions of conducting polymers under an applied potential distribution using bipolar electrodes have been carried out to prepare conducting polymers with composition gradients. Indirect electrolysis using an electrogenerated metal catalyst on bipolar electrodes successfully afforded gradually modified polymer surfaces and gradient polymer brushes. The newly designed cylinder bipolar electrode system is available for site-selective applications of electric potentials, which produced electrochemical patterning of conducting polymer films.

The lithography process simulations modeled by coarse-grained polymer techniques are reviewed. As a case of top-down process, development and rinse processes were simulated. From these simulations, line edge structure can be obtained to discuss the line edge roughness. As a case of bottom-up process, the directed self-assembly (DSA) process was simulated, and the polymer chain dynamics in the defect annihilation process can be analyzed.

In this review, we show that using two-dimensional (2D) samples suitable for atomic force microscopy (AFM) observation, especially Langmuir–Blodgett films, molecular images of various polymer structures could be obtained by tapping-mode AFM. The molecular-level observations included isolated polymer chains and their movements on substrates, 2D folded-chain crystals and their melting behavior, crystallization behavior of single isolated chains, supramolecular multistranded stereocomplex and chain packing in monolayers. The molecular-level information obtained by the direct observations should greatly improve our understanding of polymer science.

Susceptible situation of water molecules in the vicinity of lopsidedly charged copolymer films (upper) and a zwitterionic copolymer film. The charge-neutralized polymer surface is less perturbative to the structure of vicinal water. The image first published in Kobunshi 39, 445 (Hot Topics) (2014).

Because of importance of anions as analyte in diverse fields, a reliable and practical method that allows simple and rapid anion detection has been in increasing demand. To satisfy this requirement, many efforts have been made to develop optical anion sensor materials for sensor applications. This article reviews recent progress in the design and fabrication of conjugated polymer-based anion sensors. Through rational molecular design of the sensor polymers, certain structures have been found to possess desirable anion detection abilities, including enhanced binding affinity, strict size specificity and applicability to anions in an aqueous environment.

This Focus Review provides an overview of our recent study and related work on ion conductive polymer nanofibers and their applications in polymer electrolyte fuel cells. We succeeded in evaluating the intrinsic proton and anion conductivity of electrospun nanofibers and revealed their distinguished ion conductive properties, which were quite different from those of the corresponding polymer membranes. These ion conductive nanofibers have potential utility as polymer electrolyte composite membranes to improve fuel cell performance by utilizing efficient ion conduction both inside and at the surfaces of nanofibers.

This review focuses on redox-induced molecular actuation in macromolecular and self-assembled systems. Effective amplifications of conformational changes of unit molecular part are explored on the basis of three categories: polymeric system; molecular interactions; and self-assembled system. The importance of highly ordered structures is suggested to effectively amplify conformational change of small molecular unit into macroscopic deformation of bulk materials. Finally, future outlook toward electrochemical soft actuators and tips to prepare stimuli-responsive molecular assemblies, which undergo amplification in conformational change of constituent molecules, are provided.

The establishment of a Lewis acid-mediated selective propoxylation reaction using a specific borane catalyst enabled the synthesis of a novel class of PPG with an increased primary hydroxyl content of up to 70%. In addition, we developed a high yielding continuous process for producing the new PPG with a low amount of by-products by using tube reactors combined with film evaporators for by-product removal. Our new PPG achieves an excellent balance between reactivity and humidity resistance. As a result, it has important advantages for a broad area of polyurethane applications.

The segmental mobility of polymers at the interface contacted with air, a liquid and a solid is much different from that in the internal bulk phase. This review summarizes the recent studies offering a concept that the polymer interface is a useful medium for functionalization of solid polymer materials.

This review describes the N-heterocyclic carbene-catalyzed transformations of Michael acceptors that were developed by our research group, including (1) tail-to-tail dimerization of a wide variety of substrates, such as vinyl pyridines, acrylates, methacrylates and methacrylonitrile, (2) cyclotetramerization of acrylates to form trisubstituted cyclopentenones, (3) tandem oxa-Michael addition and head-to-tail dimerization of methacrolein and (4) oxa-Michael addition polymerization of hydroxyl-functionalized acrylates.

Supramolecular allosteric signal-amplification sensing (SASS) has been proposed as a novel sensing strategy and the SASS principle is to detect an allosteric regulatory signal gain from an amplifying polymer upon supramolecular interactions.

When biomaterials are implanted into an animal body, the body fluid proteins initially adsorb and then cells recognize the surfaces. Thus, an understanding of cellular responses to biomaterials is crucial for effective control of biomaterial–cell interactions. In this review, the current understanding of enhanced biocompatibility by exploring the roles of protein mediation at the interface is focused. The most promising nano-bio interfaces were explained, and different protein adsorption and cell adhesion processes were highlighted depending on their interfacial states.

For long-lasting implants of an artificial hip joint, it is necessary to reduce the wear of the acetabular liner made with polyethylene (PE). An articular cartilage-mimicking technology has been developed by grafting poly(2-methacryloyloxyethyl phosphorylcholine (MPC)) onto a highly cross-linked PE using photoinduced polymerization. The thickness of the poly(MPC) graft layer is 100–200 nm. The poly(MPC)-grafted PE has been introduced on an artificial hip joint system as a liner for lubrication. This artificial hip joint has been used clinically since 2011 and implanted on over 20 000 patients.

Poly(amino acids) and polypeptides have the potential to contribute significantly to a biomass-based and sustainable society, due to their biomass origin, functionality, and unique physical properties. The recent progress of chemo-enzymatic syntheses of polypeptides as well as studies on peptides and silks as functional and structural materials is reviewed.

This focused review is an overview of recent research on bio-based polymers produced by the controlled/living polymerization of naturally occurring or derived renewable monomers, such as terpenes, phenylpropanoids and itaconic derivatives. The judicious choice of initiating system, such as controlled/living cationic or radical polymerization, which was borrowed from conventional petrochemical monomers, not only allowed the polymerization to proceed efficiently but also produced well-defined bio-based polymers with high performance from these renewable monomers.