Controlling Toughness of Polymer-grafted Nanoparticle Composites for Impact Mitigation

Toughness in an entangled polymer network is typically controlled by the number of load-bearing topological constraints per unit volume. In this work, we demonstrate a new paradigm for controlling toughness...

Overview of methods in Oil spill technology

Over the decades oil spills have been the biggest threat to the aquatic life and to a nation’s economy. Many methods were suggested in the literature to remove the oil that is present on the surface of sea water after the spill. Hydrogel formation is one of the best technique that could be adopted to handle oil spills. Since the oil spill is a oil and water emulsion, formation of hydrogels with these emulsions could lead to the recovery of oil. The formation of hydrogels can be either physically crosslinking the polymer molecules or covalent bonding among the entangled polymer molecules. The methods of making the hydrogels conceivable to acquire surface hydrophobicity and oleophilicity. Hydrogel technology could be more cost effective and efficient in recovering the oil from the spill, eco-friendly and easy to use. It is proposed that the hydrogels could be potential candidates for handling the oil spills. The methods described in this review explains the various hydrogels that could be utilized for oil spill recovery.

Tough and Resilient Hydrogels Enabled by a Multifunctional Initiating and Cross-Linking Agent

Many high-strength hydrogels have been developed in recent years; however, few of them are both tough and resilient, and their intrinsic paradoxical nature makes designing a gel with both high toughness and high resilience a great challenge. To address this problem, we introduced both N,N,N,N-pentamethyldiethylenetriamine (PA) and N,N-methylenebisacrylamide (MBA) into polyacrylamide hydrogel networks to construct an entangled network that contains chemically cross-linked chains and branched chains simultaneously. The entanglements of branched chains can act as a physical cross-linking point to uniformly disperse stress on molecular chains, and chemical cross-linking ensures the stability of the hydrogel network. The increase in the number and length of branched chains is able to achieve an enhancement in strength while the slip of the entangled polymer chains can effectively achieve energy dissipation and can improve the toughness of the gel. Moreover, the resultant hydrogels exhibit an excellent resilience (>98%). Therefore, high toughness and resilience are achieved simultaneously. In addition, we also investigated the initiation mechanism of PA. This strategy creates a new way for the preparation of next-generation high toughness and high resilience hydrogel-based materials, which have promising applications in wearable, flexible strain/pressure sensors.

Hydrated Hydroxide Complex Dominates the AIE Property of Nonconjugated Polymeric Luminophores

Nontraditional intrinsic luminescence (NTIL) which always accompanied with aggregation-induced emission (AIE) features has received considerable attention due to their importance in the understanding of basic luminescence principle and potential practical applications. However, the rational modulation of the NTIL of nonconventional luminophores remains difficult, on account of the limited understanding of emission mechanisms. Herein, the emission colour of nonconjugated poly(methyl vinyl ether-alt-maleic anhydride) (PMVEMA) could be readily regulated from blue to red by controlling the alkalinity during the hydrolysis process. The nontraditional photoluminescence with AIE property was from the new formed p-band state, resulting from the strong overlapping of p orbitals of the clustered O atoms though space interactions. Hydrated hydroxide complexes embedded in the entangled polymer chain make big difference on the clustering of O atoms which dominates the AIE property of nonconjugated PMVEMA. These new insights into the photoemission mechanism of NTIL should stimulate additional experimental and theoretical studies and could benefit the molecular-level design of nontraditional chromophores for optoelectronics and other applications.

Hydrated Hydroxide Complex Dominates the AIE Property of Nonconjugated Polymeric Luminophores

Nontraditional intrinsic luminescence (NTIL) which always accompanied with aggregation-induced emission (AIE) features has received considerable attention due to their importance in the understanding of basic luminescence principle and potential practical applications. However, the rational modulation of the NTIL of nonconventional luminophores remains difficult, on account of the limited understanding of emission mechanisms. Herein, the emission colour of nonconjugated poly(methyl vinyl ether-alt-maleic anhydride) (PMVEMA) could be readily regulated from blue to red by controlling the alkalinity during the hydrolysis process. The nontraditional photoluminescence with AIE property was from the new formed p-band state, resulting from the strong overlapping of p orbitals of the clustered O atoms though space interactions. Hydrated hydroxide complexes embedded in the entangled polymer chain make big difference on the clustering of O atoms which dominates the AIE property of nonconjugated PMVEMA. These new insights into the photoemission mechanism of NTIL should stimulate additional experimental and theoretical studies and could benefit the molecular-level design of nontraditional chromophores for optoelectronics and other applications.