Thank you for visiting nature.com. You are using a browser version with limited support for CSS. To obtain
the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in
Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles
and JavaScript.
The cationic comb-type copolymers, which consisted of a polycation backbone grafted with high density of hydrophilic chains, form soluble and soft interpolyelectrolyte complexes with biopolymers and act as an artificial chaperone to assist in the folding of nucleic acids and peptides. The copolymers stabilize DNA duplex, triplex, and quadruplex structures and accelerate strand exchange reactions as well as assist in the folding of functional peptides into the active conformation.
Welcoming more participants in a polymer synthesis; recent years, multicomponent reactions (MCRs) have been gradually integrated into synthetic polymer chemistry, which led to a new synthetic toolbox for a range of interdisciplinary applications. In this focus review, this new trend in polymer chemistry has been summarized with including contributions from the author.
The effect of polymer design on the interfacial structure and physical properties of polymer films in water based on a poly(vinyl ether) platform with hydrophilic side-chains was examined to construct bioinert interfaces. Hydrophilic surfaces were prepared by utilizing the preferential segregation of a rubbery component in a diblock copolymer film with a glassy component, crosslinking a hydrophilic polymer, and designing an interfacial modifier with a special architecture. Interfacial structure and physical properties controlled by polymer design play important roles in determining bioinert properties.
Functionalized colloidal particles are fascinating due to their huge range of potential and reported applications. In this focus review, the recent development of a novel “interfacial photoreaction” for the preparation of functional polymer particles is summarized. This approach allows for the direct fabrication of hollow, capsular, non-spherical polymer particles from spherical polymer particles. Furthermore, the ability of this approach to synthesize morphology controlled particles possessing sophisticated functions, such as stimuli responsiveness and molecular recognition capability, was also described in this paper.
Bipolar electropolymerization is a powerful method for wirelessly achieving site-selective anisotropic modification of bipolar electrodes (BPEs) with conducting polymers. In addition, alternating current (AC) bipolar electropolymerization was developed to induce conducting polymer fibers from the terminals of BPEs that propagate parallel to the direction of the electric field. Bipolar electropolymerization is a class of next-generation electropolymerization for obtaining hybrid materials of conducting polymers and conductive objects.
Novel network structures were applied to crosslinked liquid-crystalline polymers (CLCPs) with photomechanical effects to enhance their performance and function. CLCPs with rearrangeable networks could be reshaped into 3D architectures, in contrast with conventional crosslinked polymers memorizing permanent shapes. The reshaped samples showed various photoinduced motions depending on their initial shapes. Furthermore, interpenetrating polymer networks (IPNs) were developed to improve mechanical and photoresponsive properties of CLCPs. These strategies of controlling the network structures of CLCPs could enable the versatile design of photomobile polymer materials as soft actuators.
A method to control on-demand phase transition and alignment of organic–inorganic hybrid containing lyotropic liquid crystals (LLCs) have been developed. By using polysiloxane containing hygroscopicity and photocrosslinking groups, the phase transition of the LLCs can be induced by changes in humidity. The phase-transition behavior of the LLCs in polysiloxane can be suppressed by light irradiation. Further, the author proposed new methods for vertically aligning nanochannels by using surface interaction or the spontaneous vertical-aligned nature, and photopatterning of chromonic dye aggregates.
Biodegradable injectable polymer systems exhibiting temperature-triggered formation of chemically cross-linked hydrogel were developed by “mixing strategy”. The mixture of triblock copolymer of poly(ε-caprolactone-co-glycolic acid) and poly(ethylene glycol) (PCGA-b-PEG-b-PCGA, tri-PCG) solution containing hexafunctional polythiol (DPMP) and tri-PCG with terminal acryloyl groups (tri-PCG-Acryl) solution showed temperature-responsible sol–gel transition, and the gelation was irreversible. Duration time of the gel state under physiological condition and physical property of the hydrogel could be controlled by a simple method, just changing the mixing ratio of tri-PCG-Acryl to tri-PCG.
Bulk copolymerization of bis(acryloylhydrazine) with N,N-dimethylacrylamide or N,N-diethylacrylamide yielded a transparent cross-linked polymer monolith. Upon treatment with a sodium hypochlorite solution, the cross-linked monolith dissolved in water by de-crosslinking via oxidative degradation of the diacylhydrazine moiety.
Novel polymer backbones with pendant water-soluble activated esters were synthesized by a reversible addition-fragmentation chain transfer (RAFT) polymerization technique using an acrylamide derivative bearing an N-hydroxysulfosuccinimide (sulfoNHS) ester as a monomer substrate. To synthesize glycopolymers, the substitution reaction at the sulfoNHS esters on the polymer side chain with an amine-containing saccharide derivative was performed in water. The resulting glycopolymer exhibited a strong interaction with the corresponding lectin in aqueous solution, because the saccharide moieties are multivalent.
A highly efficient and environmentally friendly graft polymerization method of methyl methacrylate (MMA) onto cotton was performed using an alkyl zinc initiator in an emulsion system. Using this method, a high-molecular weight (Mw > 106) polymer was grafted onto a cotton fiber with a high graft yield at ambient temperature. The grafted cotton fiber was characterized by FTIR, XRD, TGA, and SEM. Furthermore, the grafted cotton produced by this novel method that involved modifying the surface of the cotton improved its compatibility with a number of organic solvents.
Poly(3,4-ethylenedioxythiophene) (PEDOT) was electropolymerized from 50 mm EDOT with 1 mm tetrabutylammonium perchlorate, and acetonitrile. Stable and controllable growth of fractal PEDOT structures was achieved by varying the parameters of the voltage-driven pulsed electropolymerization. A box-counting method was used to determine the fractal dimension fdim, allowing a distinct classification of the different structures and branching. The underlying migration-driven processes enable rapid and directed growth of complex conductive structures.
Gas transport properties of novel polybenzoxazole (PBO)—silica hybrid membranes prepared via sol–gel rand different thermal treatment protocols were investigated. The hybrid membranes showed enhancements of CO2 permeability and CO2/CH4 selectivity with increasing silica content and thermal treatment temperature. The excellent CO2/CH4 separation ability might be achieved by free volume holes crated around polymer/silica interfacial area and increased intermolecular chain distance.
The aggregation states at the surface of spin-coated scaffold films composed of a multifunctional hyperbranched polymer (HBP) were characterized. While perfluorohexylethyl groups were segregated at the surface in air, the surface in water turned to be hydrophilic to minimize the free energy at the outermost region in the film. This surface reorganization was discernably faster and more remarkable for the non-annealed HBP film than for the annealed one. Fibronectin, which promoted the cellular behaviors, was more adsorbed onto the non-annealed HBP film.
We demonstrated the synthesis of fluorescent network polymers through Knoevenagel polycondensation of an (tris(p-formylphenyl)amine) with a phenylenediacetonitrile. The structure based on the electron-donor triphenylamine and electron-acceptor cyano-substituted phenylene-vinylene showed a highly efficient solid-state fluorescence. The model molecule showed a well-defined solvatofluorochromism. Surprisingly, the network polymer linked with para-phenylene-vinylene was only responsive to the solvents with a low dielectric constant and nitrobenzene. The network polymer linked with meta-phenylene-vinylene was responsive to the aromatic solvents only. The characteristic chemoselectivity was observed by the geometric effect of the network structure.
The solution-state macromolecular structure of highly 1,6-glucose-branched β-1,3-glucan (6BG3) was elucidated by modifying and complexing with chromophoric reporters. The reporter-modified 6BG3 forms the globule through the random coil-to-globule conversion process. Hybridizing 6BG3 with the polythiophene reporter affords the loose heteroduplex rather than the tight heterotriplex, indicating the formation of the loose homoduplex of 6BG3.
Thickness changes in polyvinyl acetate thin films, during the temperature cycle across the glass transition temperature (Tg) has been studied in detail. Even after enough thermal treatment done at the high-temperature side of Tg, thickness increase during cooling (negative thermal expansion) is observed. On the other hand, slow thickness decrease is observed with aging at the high-temperature side of Tg. The above interesting phenomena can be well explained by the model considering the presence and changes of the interface layer.
