In situ access to white light-emitting fluorescent polymer nanocomposites via plasma-ignited frontal polymerization

Rapid Preparation of Superabsorbent Self-Healing Hydrogels by Frontal Polymerization

Hydrogels have received increasing interest owing to their excellent physicochemical properties and wide applications. In this paper, we report the rapid fabrication of new hydrogels possessing a super water swelling capacity and self-healing ability using a fast, energy-efficient, and convenient method of frontal polymerization (FP). Self-sustained copolymerization of acrylamide (AM), 3-[Dimethyl-[2-(2-methylprop-2-enoyloxy)ethyl]azaniumyl]propane-1-sulfonate (SBMA), and acrylic acid (AA) within 10 min via FP yielded highly transparent and stretchable poly(AM-co-SBMA-co-AA) hydrogels. Thermogravimetric analysis and Fourier transform infrared spectroscopy confirmed the successful fabrication of poly(AM-co-SBMA-co-AA) hydrogels with a single copolymer composition without branched polymers. The effect of monomer ratio on FP features as well as porous morphology, swelling behavior, and self-healing performance of the hydrogels were systematically investigated, showing that the properties of the hydrogels could be tuned by adjusting the chemical composition. The resulting hydrogels were superabsorbent and sensitive to pH, exhibiting a high swelling ratio of up to 11,802% in water and 13,588% in an alkaline environment. The rheological data revealed a stable gel network. These hydrogels also had a favorable self-healing ability with a healing efficiency of up to 95%. This work contributes a simple and efficient method for the rapid preparation of superabsorbent and self-healing hydrogels.

Frontal Polymerizations: From Chemical Perspectives to Macroscopic Properties and Applications

The synthesis and processing of most thermoplastics and thermoset polymeric materials rely on energy-inefficient and environmentally burdensome manufacturing methods. Frontal polymerization is an attractive, scalable alternative due to its exploitation of polymerization heat that is generally wasted and unutilized. The only external energy needed for frontal polymerization is an initial thermal (or photo) stimulus that locally ignites the reaction. The subsequent reaction exothermicity provides local heating; the transport of this thermal energy to neighboring monomers in either a liquid or gel-like state results in a self-perpetuating reaction zone that provides fully cured thermosets and thermoplastics. Propagation of this polymerization front continues through the unreacted monomer media until either all reactants are consumed or sufficient heat loss stalls further reaction. Several different polymerization mechanisms support frontal processes, including free-radical, cat- or anionic, amine-cure epoxides, and ring-opening metathesis polymerization. The choice of monomer, initiator/catalyst, and additives dictates how fast the polymer front traverses the reactant medium, as well as the maximum temperature achievable. Numerous applications of frontally generated materials exist, ranging from porous substrate reinforcement to fabrication of patterned composites. In this review, we examine in detail the physical and chemical phenomena that govern frontal polymerization, as well as outline the existing applications.

Rapid preparation of auto-healing gels with actuating behaviour

Gels with multiple stimuli-responsive actuating behaviour have shown great potential in many applications. Nevertheless, facile approaches to rapidly preparing gel actuators are still highly needed, and obtaining gels possessing both actuating and auto-healing capabilities remains a challenge. Herein, we report the rapid preparation of gel actuators with a self-healing ability. Dual-component gels, composed of poly(BA-co-VI-co-AM) (G-1) and poly(BA-co-AA-co-AM/β-CD) (G-2) (BA = butyl acrylate, VI = N-vinyl imidazole, AM = acrylamide, AA = acrylic acid, β-CD = β-cyclodextrin), are prepared within 10 minutes (min) via biphase frontal polymerization (FP). Both G-1 and G-2 gels show excellent intrinsic self-healing properties based on hydrogen bonds, with healing efficiencies of 91% and 97%, respectively; self-healing between G-1 and G-2 also occurs due to hydrogen bonding and host-guest interactions. Moreover, dual-component gels, in terms of G-1 and G-2 bilayer gel flowers and strips, heterogeneous healed bilayer gel strips, and microfluidic-directed bilayer gel microsphere ensembles, all show actuating behaviour in acidic, alkaline and organic solutions, with actuation degrees up to 96% in 5 min. The actuation mechanism is also proposed. This work might provide new insights into fast synthesis of self-healing dual-component gels towards application in the actuator field.

Generation of a carbon dots/ammonium persulfate redox initiator couple for free radical frontal polymerization

We report a new redox initiator couple of ammonium persulfate (APS)/carbon dots (CDs) with high initiation efficiency used in frontal polymerization (FP).

Side-chain conjugated polymers for use in the active layers of hybrid semiconducting polymer/quantum dot light emitting diodes

Three monomers,M1–M3, with modified carbazole cores and styrene functionality were polymerized by RAFT. The polymers were then used in the active layers of hybrid polymer/quantum dot light emitting diodes.

Morphology control in biphasic hybrid systems of semiconducting materials

Simple blends of inorganic nanocrystals and organic (semiconducting) polymers usually lead to macroscopic segregation. Thus, such blends typically exhibit inferior properties than expected. To overcome the problem of segregation, polymer coated nanocrystals (nanocomposites) have been developed. Such nanocomposites are highly miscible within the polymer matrix. In this Review, a summary of synthetic approaches to achieve stable nanocomposites in a semiconducting polymer matrix is presented. Furthermore, a theoretical background as well as an overview concerning morphology control of inorganic NCs in polymer matrices are provided. In addition, the morphologic behavior of highly anisotropic nanoparticles (i.e. liquid crystalline phase formation of nanorod-composites) and branched nanoparticles (spatial orientation of tetrapods) is described. Finally, the morphology requirements for the application of inorganic/organic hybrid systems in light emitting diodes and solar cells are discussed, and potential solutions to achieve the required morphologies are provided.

Facile access to poly(DMAEMA-co-AA) hydrogels via infrared laser-ignited frontal polymerization and their polymerization in the horizontal direction

pH sensitive hydrogels are fabricated via infrared laser-ignited frontal polymerization (LIFP), and LIFP in the horizontal direction is employed towards dye adsorption.

In situ access to fluorescent dual-component polymers towards optoelectronic devices via inhomogeneous biphase frontal polymerization

Fluorescent dual-component poly(AM-co-NVP) and poly(HEA-co-NVP) polymers used to generate white LEDs were in situ synthesized via laser-ignited inhomogeneous biphase frontal polymerization.