The aim of this research was to develop thermo- and pH-responsive hydrogels based on H-bonds for the sustained release of the small-molecule model drug Methylene Blue (MB). The thermo- or pH-sensitive triblock copolymer based on PNIPAM or PAA was synthesized by sequential RAFT polymerization and hydrolysis. By tuning the temperature or pH, the copolymer was able to form diverse nanostructures, including core–shell micelles, electronegative or uncharged core–shell structures and 3D networks with the hydrophobic forces of PNIPAM or H-bonds between PAA and PNIPAM. Furthermore, the reversible sol–gel transition of the copolymers was modulated by temperature (∼37 °C), pH (∼5) and concentration (∼7 wt%). The drug release potential was evaluated via in vitro injection of copolymer hydrogels into a simulated human body device. The copolymer hydrogels exhibited a sustained drug release behavior and a low instantaneous drug concentration. The MTT studies revealed that there is no noticeable cytotoxicity of NDB or NDA hydrogels against cells. Thus, the tunable drug release efficiency suggests the possibility of PNIPAM- and PAA-based environment responsive hydrogels being applied as drug carrier systems.

A robust superhydrophobic coating based on Ni/WS₂was fabricated successfully through a simple one-step electrodeposition process. This metal-caramic composite coating showed excellent self-cleaning and corrosion resistance properties.

The multi-stimuli-responsive amphiphilic ABC triblock copolymer of poly(methyl methacrylate)-block-poly[N,N-(dimethylamino) ethyl methacrylate]-block-poly(N-isopropylacrylamide) (PMMA-b-PDMAEMA-b-PNIPAM) was synthesized by sequential reversible addition–fragmentation chain transfer (RAFT) polymerizations. Due to the pH- and thermo-responsive blocks of PDMAEMA and thermo-responsive blocks of PNIPAM, the copolymer solution properties can be manipulated by changing the parameters such as temperature and pH, and it formed diverse nanostructures and had gel behavior in different conditions. In detail, when the pH was below 7.3, the pK_a of DMAEMA, tertiary amino groups were protonated, the polymer micellar solution like weak gel changed into free-standing gel at around 40 °C even at a low concentration of 2 wt%. Further, the gel behavior and morphology of the system were studied by rheology, turbidimetry measurements, transmission electron microscopy (TEM) and scanning electron microscopy (SEM), respectively. When the pH was above the pK_a, the triblock copolymer self-assembled into diverse micellar structures including shell–core, corona–shell–core and shell–shell–core nanoparticles as the temperature increased, but no free-standing gelation. The two-step thermo-responsive behavior, corresponding to the different LCSTs of PNIPAM block and DMAEMA block, was evidenced by turbidity analysis. The assembled structures rapidly collapsed due to the enhanced hydrophobic interaction when the temperature further increased. Dynamic light scattering (DLS) was used to confirm the transitions.

The mechanical properties of superhydrophobic surfaces based on nickel composite coatings was enhanced by co-deposition of tungsten carbide. After modified by stearic acid, the surfaces showed excellent water-repellence and abrasive resistance.

Organic solvent-soluble N-maleoyl-chitosan (NMCS) was synthesized by reaction of chitosan with maleic anhydride (MAH) in N, N-dimethylformamide (DMF). N-maleoyl-chitosan-graft-poly(N-isopropylacrylamide) (NMCS-g-PNIPAAm) copolymer hydrogel was prepared via free radical polymerization by electron beam (EB) irradiation. The copolymer obtained was analysed by FT-IR, XRD and thermal gravimetric analysis (TGA). It was found that the grafting yield and grafting efficiency increased with increasing radiation absorbed dose and monomer amount, and then decreased. The swelling ratio of the copolymer hydrogel was low at pH 4–5, and LCST of the hydrogel was around 32°C.