Surface Chemistry in Environmental Degradation of Polymeric Solids.

Microplastics (MPs) cause significant adverse environmental effects. To address this issue, a scientific approach for understanding the formation of MPs is essential. In this Perspective, we summarize the three typical degradation behaviors of polymeric solids from a surface chemistry perspective: chemical degradation, biodegradation, and mechanical degradation.

Controlling Microstructure-Transport Interplay in Poly(ether--amide) Multiblock Copolymer Gas Separation Membranes.

In this study, we investigated the effect of morphology on the gas-transport properties of a poly(ether--amide) (PEBA) multiblock copolymer. We annealed the copolymer samples and varied the annealing temperature to evaluate the influence of changes in the microstructure on the gas transport properties of PEBA. In addition, we used time-resolved attenuated total reflection Fourier transform infrared spectroscopy to evaluate the diffusion coefficient of CO in PEBA based on the Fickian model.

Promotion of glyoxylic acid penetration into human hair by glycolic acid.

Objective: Glyoxylic acid (GA) is widely used as a straight perming agent for hair care products, however, advanced GA penetration-enhancing agents are desired due to the peculiar odour and hair colour fading caused by the continuous use of GA products. Hence, it is important to develop a penetration-enhancing agent that helps minimize the GA concentration. We have found that the combined use of GA and glycolic acid (GCA) has a strong hair straightening effect.

Circular Polarization Luminescence of Groove Anchor Driving Optically Active Poly(methyl methacrylate) Stereocomplexes.

This paper presents a facile method for fabricating a thin-film sample with a high asymmetry value of induced circularly polarized luminescence (iCPL) (|g| = 2.0 × 10). The method involves mixing stereoregular poly(methyl methacrylate) (PMMA) and chiral chromophore (2,2,2-trifluoro-1-(9-anthryl)ethanol (TFAE)) to form a complex with a dynamic helical conformation of poly(methyl methacrylate) (PMMA) associated with TFAE via hydrogen bonding.

Neutron Reflectometry & Simultaneous Measurements of Rheology and Small Angle Neutron Scattering Studies for Polyether Modified Silicone Vesicle Systems.

Polyethyleneglycol 12 mol / polydimethylsiloxane co-polymer (PEG-12 dimethicone) is a type of polyether modified silicone (PEMS), which can form a lamellar liquid crystalline phase, and is widely used in cosmetics. The structural changes of PEG-12 dimethicone caused by water contents as well as shear flow were evaluated using simultaneous measurements of rheology and small angle neutron scattering (Rheo-SANS) and neutron reflectometry (NR). At high PEG-12 dimethicone concentrations (≥ 36 wt%), a reorientation of plate-like lamellar structures were observed and the neutral orientation was the most favorable.

Control cell migration by engineering integrin ligand assembly.

Advances in mechanistic understanding of integrin-mediated adhesion highlight the importance of precise control of ligand presentation in directing cell migration. Top-down nanopatterning limited the spatial presentation to sub-micron placing restrictions on both fundamental study and biomedical applications. To break the constraint, here we propose a bottom-up nanofabrication strategy to enhance the spatial resolution to the molecular level using simple formulation that is applicable as treatment agent.

Preparation and characterization of an imogolite/chitosan hybrid with pyridoxal-5'-phosphate as an interfacial modifier.

Imogolite/chitosan hybrid films were prepared using pyridoxal-5'-phosphate (PLP) as an interfacial modifier. Thermogravimetric analysis and spectroscopic measurements revealed that the phosphate group of PLP was adsorbed on the imogolite. Furthermore, rheological measurements suggested that the PLP-modified imogolites (PLP-imogolite) had strong interactions with chitosan in solution.

Specific deformation behavior of isotactic polypropylene films under a multiaxial stress field.

The specific deformation behavior of crystalline polymer films, namely unoriented crystallized isotactic polypropylene ( PP) films, was investigated under a multiaxial stress field. Changes in the aggregation structure of the films were investigated during the bulge deformation process using small-angle X-ray scattering, wide-angle X-ray diffraction (WAXD) measurements, and polarized high-speed-camera observations. The films had a thickness of approximately 10 μm.

Critical In-Plane Density of Polyelectrolyte Brush for the Ordered Hydrogen-Bonded Structure of Incorporated Water.

A polymer electrolyte brush is a reasonable platform to confine water molecules within a nanoscopic area to study their role in the function of interacting media because of their adjustable nanospace and charge by changing the in-plane density and side chains of the brush. Here, we demonstrate how the in-plane spacing of cationic polymer brush chains, poly[2-(methacryloyloxy)ethyltrimethylammonium chloride] (PMTAC), affects the hydrogen bond configuration of incorporated water using soft X-ray emission spectroscopy. At the critical in-plane density σ = 0.

Modulation of Double Zwitterionic Block Copolymer Aggregates by Zwitterion-Specific Interactions.

Transformable double hydrophilic block copolymer assemblies are valid as a biocompatible smart macromolecular system. The molecular mechanisms in the spontaneous assembly of double zwitterionic diblock copolymers composed of a poly(carboxybetaine methacrylate) (PCB2) and a poly(sulfobetaine methacrylate) (PSB4) chains (PCB2--PSB4) were investigated by the modulation of the aggregates in response to nondetergent zwitterions. The PCB2--PSB4 diblock copolymers with a high degree of polymerization PSB4 block produced aggregates in salt-free water through "zwitterion-specific" interactions.

Cononsolvency of Poly[2-(methacryloyloxy)ethyl phosphorylcholine] in Ethanol-Water Mixtures: A Neutron Reflectivity Study.

Molecular mechanisms underlying the cononsolvency, a re-entrant coil-to-globule-to-coil conformational transition of polymer chains in mixtures of two good solvents, of poly[2-(methacryloyloxy)ethyl phosphorylcholine] (PMPC) in ethanol-water binary mixtures were complementarily investigated. This was accomplished by following a statistical mechanical model for competitive hydrogen bonding combined with the cooperative solvation concept as well as neutron reflectivity (NR) experiments employing contrast variation in the cononsolvents. The experimental re-entrant aggregation of the PMPC chains in ethanol-water mixed solvents, obtained on the basis of turbidity was accurately reproduced by theoretical calculations.

Probing the in-plane liquid-like behavior of liquid crystal elastomers.

When isotropic solids are unequally stretched in two orthogonal directions, the true stress (force per actual cross-sectional area) in the larger strain direction is typically higher than that in the smaller one. We show that thiol-acrylate liquid crystal elastomers with polydomain texture exhibit an unusual tendency: The true stresses in the two directions are always identical and governed only by the area change in the loading plane, independently of the combination of imposed strains in the two directions. This feature proves a previously unidentified state of matter that can vary its shape freely with no extra mechanical energy like liquids when deformed in the plane.

Actuator Performance of Dielectric Elastomers Comprising Hydrogenated Carboxylated Acrylonitrile-Butadiene Rubber/Nitrile Group-Modified Titanium Oxide Particles.

We prepared a dielectric elastomer actuator composed of hydrogenated carboxylated acrylonitrile-butadiene rubber (HXNBR)/nitrile group (CN)-modified and non-modified titanium oxide (TiO) particles with insulation properties. The CN group-containing silane coupling agent was synthesized via a thiol-ene reaction between acrylonitrile and 3-mercaptpropyltrimethoxysilane and immobilized onto the TiO particle surface. The HXNBR/CN-modified and non-modified TiO particle composite elastomer showed a high relative dielectric constant and generated stress in a low electric field.

Exploring the Mesoscopic Morphology in Mussel Adhesive Proteins by Soft X-ray Spectromicroscopy.

Marine mussels efficiently adhere under wet conditions by precisely controlling the hierarchical structure of the adhesive plaque through sequential mussel foot protein secretion in the foot-tip cavity. Chemical analysis of the non-uniform mussel plaque morphology has been performed using spectromicroscopy; however, the mesoscopic morphology has not been elucidated yet because of the limited spatial resolution of conventional chemical imaging techniques. We investigated the chemical speciation in the non-uniform mussel plaque morphology employing scanning transmission soft X-ray spectromicroscopy (STXM).

Actuator Performance of a Hydrogenated Carboxylated Acrylonitrile-Butadiene Rubber/Silica-Coated BaTiO Dielectric Elastomer.

We synthesized silica-coated barium titanate (BaTiO) particles with different silica shell thicknesses and evaluated the effect of silica coating on the relative dielectric properties of silica-coated BaTiO particles. Furthermore, composite elastomers were prepared using hydrogenated carboxylated acrylonitrile-butadiene rubber (HXNBR) with a high relative dielectric constant (ε) and silica-coated BaTiO particles, and their performance as an actuator was evaluated. Both ε and relative dielectric loss of non-coated BaTiO particles increased at low frequencies (<200 Hz) associated with ionic conduction.

Complex Network Representation of the Structure-Mechanical Property Relationships in Elastomers with Heterogeneous Connectivity.

The complicated structure-property relationships of materials have recently been described using a methodology of data science that is recognized as the fourth paradigm in materials science. In network polymers or elastomers, the manner of connection of the polymer chains among the crosslinking points has a significant effect on the material properties. In this study, we quantitatively evaluate the structural heterogeneity of elastomers at the mesoscopic scale based on complex network, one of the methods used in data science, to describe the elastic properties.

Application of Synchrotron Radiation X-ray Scattering and Spectroscopy to Soft Matter.

Light produced by synchrotron radiation (SR) is much brighter than that produced by conventional laboratory X-ray sources. The photon energy of SR X-ray ranges from soft and tender X-rays to hard X-rays. Moreover, X-rays become element sensitive with decreasing photon energy.

Hydration State Variation of Polyzwitterion Brushes through Interplay with Ions.

Polyzwitterions have emerged as a new class of antifouling materials alternating poly(ethylene glycol). The exemplary biopassivation and lubrication behaviors are often attributed to the particular chemical structure of zwitterions, which involve a large dipole moment of the charged groups and a neutral net charge, while the hydration state and dynamics also associate with these characteristics. Polymer brushes composed of surface-tethered polyzwitterion chains produced by surface-initiated controlled radical polymerization have been developed as thin films which exhibit excellent antifouling and lubrication properties.

Relationship between the Relative Dielectric Constant and the Monomer Sequence of Acrylonitrile in Rubber.

Acrylonitrile-butadiene rubbers (NBRs) have a lower glass transition temperature ( ) and a higher dielectric constant than other rubbers. To understand how a low and a high dielectric constant are compatible, we focused on the acrylonitrile (AN) monomer sequence in rubber and synthesized random and alternating copolymers to evaluate the effect of the sequence. The AN monomer sequence dependence of the relative dielectric constant was investigated by the C-N stretching vibration of the nitrile group through Fourier transform infrared spectroscopy and internal rotation potential energy measurements around the C-C bond within the nitrile group based on dimer model calculations.

Synthesis and Hydration Behavior of a Hydrolysis-Resistant Quasi-Choline Phosphate Zwitterionic Polymer.

A hydrolysis-resistant polymer bearing new quasi-choline phosphate (quasi-CP) structures as side groups, poly(2-methacryloyloxyethyl choline methylphosphonate) (), was designed and synthesized. Radical polymerization and sub-surface-initiated radical polymerization were used to prepare homopolymer and polymer brush on polymer substrates. Hydrolytic stability and hydrophilicity of the polymer were confirmed by nuclear magnetic resonance and contact angle measurements.

Molecular Aggregation Structure and Surface Properties of Biomimetic Catechol-Bearing Poly[2-(perfluorooctyl)ethyl acrylate] and Its Application to Superamphiphobic Coatings.

The molecular aggregation structure and surface properties of a catechol-bearing fluoropolymer, P(FAC--DOPAm), which was synthesized by conventional radical copolymerization of 2-(perfluorooctyl)ethyl acrylate (FAC) and -(3,4-dihydroxyphenethyl)acrylamide (DOPAm), and its application to the superamphiphobic surfaces are presented. The crystallinity of P(FAC--DOPAm) was lower than that of poly[2-(perfluorooctyl)ethyl acrylate] (PFAC). The perfluoroalkyl (R) groups were ordered on the surface with CF terminals exposed to air, and the R ordering was influenced by thermal history: the thermally annealed film exhibited higher R ordering than the unannealed one.

Functionalization of Metal Surface via Thiol-Ene Click Chemistry: Synthesis, Adsorption Behavior, and Postfunctionalization of a Catechol- and Allyl-Containing Copolymer.

Surface functionalization tailors the interfacial properties without impacts on the mechanical strength, which is beneficial for industry and daily applications of various metallic materials. Herein, a two-step surface functionalization strategy, (1) catechol-mediated immobilization of clickable agent and (2) postfunctionalization based on thiol-ene click reaction, is achieved using a copolymer, namely poly[2-(methacryloyloxy)ethylundec-10-enoate]--(-(3,4-dihydroxyphenethyl) methacrylamide) [P(MEUE--DPMAm)]. To reduce the potential side reactions of allylic double bonds in allyl methacrylate during the polymerization, the MEUE are designed and synthesized with better control over the polymer chain growth.