Themed collection Polymer Networks
Materials development in stretchable iontronics
By classifying stretchable ionic materials into three types of components (ionic conductors, ionic semiconductors, and ionic insulators), we summarized materials development in stretchable iontronics in terms of molecular interactions.
Photoinduced deformation of amorphous polyimide enabled by an improved azobenzene isomerization efficiency
A newly designed azo-PI, without pre-stretching or polarized-light irradiation, exhibits reversible bending behaviors under alternate UV and visible light irradiation, providing a facile route to deformable 2D/3D structure actuators.
Thermoresponsive ionogels with switchable adhesion in air and aqueous environments induced by LCST phase behavior
We report a thermoresponsive ionogel with switchable adhesion both in air and aqueous environments, which can be utilized for the underwater on demand capture and release.
Reinforcement of ultrahigh thermoresistant polybenzimidazole films by hard craters
Ultrahigh thermoresistant polybenzimidazole films with uniform pores and hard craters on the surface were prepared by a silica template method. The pore and crater formation enhanced elongation and Young's modulus.
Controlling the dynamics of elastomer networks with multivalent brush architectures
A method for lowering the activation energy of melting while improving the mechanical robustness of an elastomer was achieved using bottlebrush topologies. This system has the potential to realize self-healing materials with enhanced processability.
Single microgel degradation governed by heterogeneous nanostructures
The real-time visualization via high-speed atomic force microscopy revealed that single microgel exhibit heterogeneous degradation behavior.
Relatively homogeneous network structures of temperature-responsive gels synthesized via atom transfer radical polymerization
DLS measurements revealed that temperature-responsive gels prepared by ATRP have more homogeneous networks than those by free radical polymerization. The standard deviation of the scattered intensity is used to quantify the network inhomogeneity.
Environmentally responsive hydrogel composites for dynamic body thermoregulation
Environmentally responsive hydrogel composites embedded with submicron-sized spherical silica particles for the modulation of the mid-infrared radiation derived from the Bragg reflection are therein designed for personalized body thermoregulation.
Three-dimensional liquid crystal polymer actuators assembled by athermal photo-welding
We propose a strategy based on athermal photo-welding to construct 3D actuators assembled by azobenzene-containing linear liquid crystal polymers with different orientations, which demonstrate diverse deformations of curling, winding, and unwinding.
Controlling mechanical properties of ultrahigh molecular weight ion gels by chemical structure of ionic liquids and monomers
The effect of ionic liquid and monomer structures on the mechanical properties of ultrahigh molecular weight ion gels was investigated.
Preparation of a novel regenerated silk fibroin-based hydrogel for extrusion bioprinting
A bio-printable hydrogel of regenerated silk fibroin with high-molecular-weight was prepared from its aqueous solution with the help of urea involvement, and the gelation process and properties of the hydrogel was investigated.
Temperature- and strain-dependent transient microstructure and rheological responses of endblock-associated triblock gels of different block lengths in a midblock selective solvent
Using RheoSAXS, the change in microstructure of PMMA-PnBA-PMMA triblock gels in 2-ethyl-1-hexanol subjected to oscillatory shear and temperature has been characterized.
Ionic shape memory polymer gels as multifunctional sensors
The wearable shape memory multifunctional sensor array is capable of sensing both direction and quantity of bending displacement and velocity.
Effective pH-regulated release of covalently conjugated antibiotics from antibacterial hydrogels
pH-regulated release of antibiotics is achieved by conjugation with the hydrogel matrix through the reversible imine bond.
Molecular dynamics study of the swelling and osmotic properties of compact nanogel particles
Molecular architecture of nanogel particle.
Dually-dynamic covalent tetraPEG hydrogels end-linked with boronate ester and acylhydrazone groups
TetraPEG hydrogels cross-linked via both boronic acid ester and acylhydrazone dynamic covalent bonds were developed. Adjustment of the fraction of each type of cross-link allows the fine-tuning of hydrogel behavior between self-repair and stability.
Effect of anions on the phase transition temperature of two structurally isomeric polymers: poly(N-isopropylacrylamide) and poly(2-isopropyl-2-oxazoline)
In chaotropic solution, the different lower critical solution temperature (LCST) increments of two structural isomers, namely, poly(N-isopropylacrylamide) (PNIPAAm) and poly(2-isopropyl-2-oxazoline) (PiPOx), is studied.
An extreme toughening mechanism for soft materials
This work utilizes a combined effort of experiment and theory to report a new mechanism and scaling law to account for extreme toughening of diverse soft materials.
Interfacial self-assembly of SiO2–PNIPAM core–shell particles with varied crosslinking density
The effect of crosslinker content and core size on the interfacial self-assembly of batch-type PNIPAM@SiO2 core–shell particles was studied, revealing parameter windows for chain phases, rhomboid packing and stable d = 448 nm non-close packed cores.
Tailoring intermolecular interactions in ion gels with rationally designed phosphonic acid polymers
Design strategies of phosphonic acid polymers established advanced ion gels with high ionic conductivity, mechanical strength, and self-healing ability via a configurable balance of ionic and hydrogen bonding interactions at the molecular level.
Effects of cyclic and acyclic amidine side-chains on the properties of polysiloxane ionomers constructed in situ from three uncharged components
Small structural changes to side chain groups have large consequences to the structures and dynamics of corresponding polysiloxane-based ionomers.
One-pot synthesis of structure-controlled temperature-responsive polymer gels
The simultaneous use of metal Lewis acids and photo-radical generators for dithioesters, which are the common dormant species for cationic and radical polymerization, made it possible to convert a cationic species into a radical by photoirradiation.
Shrinking rates of polymer gels composed of star-shaped polymers of N-isopropylacrylamide and dimethylacrylamide copolymers: the effect of dimethylacrylamide on the crosslinking network
The effects of monomer arrangement and composition for star-shaped polymers composed of N-isopropylacrylamide and N,N-dimethylacrylamide on the shrinkage behavior of the gels is studied, to increase their shrinkage rates without reducing the network densities of the gels.
Synergetic improvement in the mechanical properties of polyurethanes with movable crosslinking and hydrogen bonds
The synergetic effect of the movable crosslinking and the hydrogen bonds in γCDMe(x)PU contributed to the simultaneous increase in the mechanical properties such as Young’s modulus and toughness.
Time–strain inseparability in multiaxial stress relaxation of supramolecular gels formed via host–guest interactions
Time and strain effects on stress are not separable in supramolecular gels utilizing host–guest interactions in contrast to a dual cross-link gel with covalent and transient cross-links in which the separability was validated by the same assessment.
Bond strength regime dictates stress relaxation behavior
This work utilizes in situ crosslinked dynamic networks to show differences in stress-relaxation behavior depending on the bond strength of the metal–ligand crosslinker used.
Biomass-derived isosorbide-based thermoresponsive hydrogel for drug delivery
Bio-based hydrogel films are fabricated by reacting a glycerol ethoxylate-based triazide and an isosorbide-based dialkyne via Cu(I)-catalyzed photo-click reaction. These materials are suitable candidates for the delivery of therapeutic molecules.
Strength of fluid-filled soft composites across the elastofracture length
This work probes the mechanical strength of composite hydrogels as the assembly size scale of the hydrophobic secondary phase transitions across the elastofracture length.
Brownian simulations for tetra-gel-type phantom networks composed of prepolymers with bidisperse arm length
Using Brownian dynamics simulations, we studied the mechanical properties of tetra-gel-type networks with varying arm length contrast of prepolymers to modulate the number of double linkages.
Synthesis of degradable double network gels using a hydrolysable cross-linker
Biodegradable double network (DN) gels with remarkably high mechanical strength and toughness were synthesised. The biodegradable DN gels can be potentially applied in biomedical applications such as cartilage regeneration.
Fabrication of a tunable photothermal actuator via in situ oxidative polymerization of polydopamine nanoparticles in hydrogel bilayers
In situ oxidative polymerization of polydopamine in a hydrogel matrix enables tunable photothermal actuation of a hydrogel actuator.
Linking microscopic structural changes and macroscopic mechanical responses in a near-ideal bottlebrush elastomer under uniaxial deformation
Structural changes and mechanical responses of a model bottlebrush elastomer with a controlled network structure were investigated by small-angle X-ray scattering coupled with uniaxial tensile testing.
Interpenetrated triple network polymers: synergies of three different dynamic bonds
Triply interpenetrated networks were made with a unique dynamic linker in each network. The linkers were hydrogen bonds, boronic esters and Diels–Alder adducts. Triply dynamic materials had superior properties compared to doubly dynamic analogues.
Structure–property correlation of crosslinked domain hydrogels exhibiting thermoresponsive mechanical toughening and hybridization with photoluminescent carbon dots
A smart gel material exhibiting a simultaneous change in mechanical properties and photoluminescence is developed.
Core–shell microgels having zwitterionic hydrogel core and temperature-responsive shell prepared via inverse miniemulsion RAFT polymerization
The temperature-responsive core–shell microgels comprising PMPC core and side-chain oligo(ethylene glycol) polymer shell were prepared via inverse miniemulsion RAFT polymerization using a water-soluble emulsifier with RAFT agent terminus.
Linking cavitation and fracture to molecular scale structural damage of model networks
Needle-induced cavitation is performed on model end-linked gels to experimentally determine when soft solids will fail through either cavitation or fracture. Attention is also paid to when cavitation damages the network structure.
Ionic group-dependent structure of complex coacervate hydrogels formed by ABA triblock copolymers
We investigated the effect of ion pairs on the structure of complex coacervate core hydrogels (C3Gs) using small-angle X-ray/neutron scattering. The ratio between ammonium and guanidinium groups modulates both structure and salt-responsiveness of C3Gs as stimuli-responsive materials.
Mechanochromic elastomers with different thermo- and mechano-responsive radical-type mechanophores
Mechanochromic elastomers with different thermo- and mechano-responsive radical-type mechanophores are prepared and their sensitivity to heat and mechanical force is investigated.
A strain-stiffening seal is soft to accommodate installation but stiff to block fluid flow. Leak by elastic deformation or rupture? We construct diagrams in which the two modes of leak are demarcated.
Visible light triggered controlled formation of rapidly self-healing hydrogels based on thiol–disulfide exchange
Biodegradable disulfide-crosslinked hydrogels were constructed via the visible light triggered thiol–disulfide exchange reaction under mild gelation conditions, and the hydrogel coatings could be rapidly self-healed in 10 min under ambient conditions.
Chiral graphene-based supramolecular hydrogels toward tumor therapy
D-Phenylalanine-based (DPFEG) hydrogel co-assembled with GO and its handedness reversal induced the selective delivery of chiral anticancer drugs under IR irradiation for tumor therapy.
Multi-level encryption of information in morphing hydrogels with patterned fluorescence
We describe a strategy to improve information security by combining shape morphing and patterned fluorescence in a bilayer hydrogel. The information concealed in the hydrogel becomes readable after shape recovery and under UV light irradiation.
Impact of dynamic covalent chemistry and precise linker length on crystallization kinetics and morphology in ethylene vitrimers
Vitrimers, dynamic polymer networks with topology conserving exchange reactions, can lead to unusual evolution of the melting temperature and crystal structure of ethylene networks.
About this collection
This Polymer Chemistry and Soft Matter cross-journal collection on Polymer Networks is Guest Edited by Yukikazu Takeoka (Nagoya University), Matsumoto Akira (Tokyo Medical & Dental University), Akira Kakugo (Hokkaido University), Jianping Gong (Hokkaido University) and Alfred Crosby (University of Massachusetts Amherst). This collection covers the physical properties, applications of, and synthetic strategies towards polymer networks, including solvent-free polymer networks, stimuli responsive polymer gels and elastomers, and polymer networks in sustainable development. The collaborative joint special issue is inspired by the fact that polymer networks truly span from the molecular chemical to the materials level.