State Key Laboratory of Macromolecular Engineering

Abstract Block copolymer particles with controlled morphologies are of great significance in nanomaterials and nanotechnology. However, ordered inverse morphologies are difficult to achieve due to complex mechanism and formation conditions. Here we report scalable preparation of amphiphilic alternating block copolymer particles with inverse bicontinuous mesophases via polymerization-induced self-assembly (PISA). Concentrated dispersion copolymerizations (up to 40% solid content) of styrene (St) and pentafluorostyrene (PFS) employing a short poly( N,N -dimethylacrylamide) (PDMA 29 ) stabilizer block lead to the formation of well-defined, highly asymmetric PDMA 29 - b -P(St- alt -PFS) x block copolymers with precise compositions and various morphologies, from simple spheres to ordered inverse cubosome mesophases. The particle morphology is affected by the molecular weight, solid content, and nature of the cosolvents. The cubosome structure is confirmed by electron microscopies and small angle X-ray scattering spectroscopy. This scalable PISA approach offers facile access to ordered inverse mesophases, significantly expanding the PISA morphology scope and enabling its applicability to the materials science fields.

Abstract The organization of nanoparticles in constrained geometries has attracted increasing attention due to their promising structures and topologies. However, the control of hierarchical structures with tailored periodicity at different length scales and topology stabilization in a dynamic environment are very limited and challenging. Herein, through self‐assembly of cellulose nanocrystals (CNCs) within an in situ formed hydrogel sheath using a simple microfluidic strategy, a new breed of liquid crystal (LC) fibers with hierarchical core–sheath architectures, metaperiodic cholesteric alignments, and 3D topological defects, termed as liquid metacrystal (LMC) fibers, is created. The resulting LMC fibers not only exhibit vivid, tunable interference colors, and even inverse optical activity but also have a unique ability to precisely regulate linearly and circularly polarized light in a half‐sync/half‐async form. Furthermore, robust hydrogel sheath enables the LMCs with alignment stability and configuration programmability during drying, which endows the unprecedented freedom to tailor different optical appearances for polarization‐based encryption and recognition. This work opens an avenue toward the fabrication of length‐scale colloidal LCs with continuous and stable topologies and expands the application regimes of LC materials in chiral optics and smart textiles.

Graphene and MWCNTs were firmly immobilized on the fiber surface by covalent networks generated from the condensation of the reactive dispersant.

Two-dimensional nanosheet membranes with responsive nanochannels are appealing for controlled mass transfer/separation, but limited by everchanging thicknesses arising from unstable interfaces. Herein, an interfacially stable, thermo-responsive nanosheet membrane is assembled from twin-chain stabilized metal-organic framework (MOF) nanosheets, which function via two cyclic amide-bearing polymers, thermo-responsive poly(N-vinyl caprolactam) (PVCL) for adjusting channel size, and non-responsive polyvinylpyrrolidone for supporting constant interlayer distance. Owing to the microporosity of MOF nanosheets and controllable interface wettability, the hybrid membrane demonstrates both superior separation performance and stable thermo-responsiveness. Scattering and correlation spectroscopic analyses further corroborate the respective roles of the two polymers and reveal the microenvironment changes of nanochannels are motivated by the dehydration of PVCL chains.

Highly conductive composites with an interconnected nanocarbon network were prepared <italic>via</italic> an electrostatic self-assembly and hot-pressing process.

MXene is becoming more and more active in the field of anticorrosion coatings. In this work, Ti3C2 nanosheets were modified with dopamine monomer and then introduced into waterborne epoxy coatings (EP). Composite coatings with unmodified Ti3C2 nanosheets were also prepared for comparison. Anticorrosion properties of the coatings were evaluated via electrochemical impedance spectroscopy and salt spray tests in detail. Dopamine monomer was readily attached to Ti3C2 nanosheets via chemical bond and saturated at 0.075 mg/mg Ti3C2. The modified Ti3C2 (D-Ti3C2) showed slightly deteriorated dispersibility in water but better dispersibility in waterborne epoxy resin relative to unmodified Ti3C2. The impedance modulus of D-Ti3C2 coatings achieved four and two orders of magnitude enhancement compared with EP and unmodified Ti3C2 coatings, respectively. The addition of D-Ti3C2 reduced the water absorption of EP by 80% after a prolonged immersion process. Superior barrier ability and enhanced dispersion of D-Ti3C2 nanosheets were responsible for the efficient enhancement of the anticorrosion performance of waterborne epoxy resin coating.

The formation of a homogeneous graphene dispersion is a fundamental prerequisite for the preparation of high-performance graphene-based materials, yet it remains a challenge to obtain, particularly at high concentrations, meanwhile possessing a film-forming ability. In the present work, a new TSiPD•+ molecule, consisting of a conjugated core and terminal silanol groups, was synthesized. With the aid of the TSiPD•+, a stable graphene dispersion in water was obtained with a concentration up to 10 mg/mL. More interestingly, the graphene dispersion was able to self-cross-link, after direct casting on substrates, forming highly conductive graphene films with good mechanical strength and excellent solvent resistance. The outstanding performance of the graphene films is owed to the condensation of the silanol groups in the TSiPD•+ molecules. The use of the aqueous graphene as conductive ink for paper, glass, and even polymer films was demonstrated.

Colloidal liquid crystals (LCs) formed by nanoparticles hold great promise for creating new structures and topologies. However, achieving highly ordered hierarchical architectures and stable topological configurations is extremely challenging, mainly due to the liquid-like fluidity of colloidal LCs in nature. Herein, an innovative synchronous nanofluidic rectification (SNR) technique for generating ultralong graphene oxide (GO) liquid crystal (GOLC) fibers with hierarchical core-skin architectures is presented, in which the GO sheet assemblies and hydrogel skin formation are synchronous. The SNR technique conceptually follows two design principles: horizontal polymer-flow promotes the rapid planar alignment of GO sheets and drives the chiral-reversing of cholesteric GOLCs, and in situ formed hydrogel skin affords some protection against environmental impact to maintain stable topological configurations. Importantly, the dried fibers retain the smooth surface and ordered internal structures, achieving high mechanical strength and flexibility. The linear and circular polarization potential of GOLC fibers are demonstrated for optical sensing and recognition. This work may open an avenue toward the scalable manufacture of uniform and robust, yet highly anisotropic, fiber-shaped functional materials with complex internal architectures.

Polysiloxane-based artificial skins are able to emulate the mechanical and barrier performance of human skin. However, they are usually fabricated in vitro, restricting their diverse applications on human body. Herein, we presented one-component waterborne cross-linkable polysiloxane coatings prepared from emulsified vinyl dimethicone, emulsified hydrogen dimethicone, and Karstedt catalyst capsules that were first synthesized by solvent evaporation method. The coating had good storage stability and meanwhile could form an elastic film quickly through merging of silicone oil droplets and subsequent hydrosilylation reaction. It was found that the mass ratio of vinyl dimethicone emulsion/hydrogen dimethicone emulsion (V/H), and the dosage of Karstedt catalyst capsules (K/(V + H)) were critical to the curing time, morphology, and mechanical properties of the coatings. With appropriate values of V/H and K/(V + H), the polysiloxane film had the mechanical performance comparable to that from solvent-based one. The coating could be topically applied to human skin in vivo and in situ turned into an elastic, invisible thin film with good water resistance. In contrast to those reported polysiloxane materials, the one-component waterborne polysiloxane coating was nontoxic and convenient for in vivo application on human body, making it be a promising candidate as artificial skin in the fields of cosmetics, medical treatment, and E-skin.