Thermoresponsive polymers that are pH tunable were successfully synthesized by a combination of atom transfer radical polymerization (ATRP) and Cu(I)-catalyzed 1,3-dipolar cycloaddition of azide and alkynes (click chemistry). ATRP was employed to synthesize poly(2-hydroxyethyl methacrylate) (PHEMA), followed by introduction of alkyne groups using pentynoic acid, leading to PHEMA-alkyne. 2-Azidoethylamine, 2-azido-N,N-dimethylethylamine, and 2-azido-N,N-diethylethylamine were added to the PHEMA-alkyne backbone via click chemistry. Molecular weight, molecular weight distribution, and click reaction efficiency were determined by gel permeation chromatography (GPC) and 1H NMR spectroscopy. The average molecular weight (M n) of the resulting polymers ranged from 5.6 × 104 to 7.0 × 104 depending on the molecular architecture. The molecular weight distribution was low (M n/M n = 1.25−1.35). The transmission spectra of the 0.1 wt % aqueous solutions of the resulting polymers with different pH values at 650 nm were measured as a function of temperature. Results showed that the lower critical solution temperature (LCST) could be dramatically affected by solution pH. To give additional evidence for pH-responsive thermal transition, in-situ temperature-dependent 1H NMR measurements in deuterated water (0.01 wt %) were conducted. The LCST values measured by in-situ 1H NMR correlated well with those determined by turbidimetry.

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Solution‐processed polar hydroxyl containing polymers such as poly(4‐vinylphenol) are widely utilized in organic filed‐effect transistors (OFETs) due to their high dielectric constant (k) and excellent insulating properties owing to the crosslinking through their hydroxyl groups. However, hydroxyl functionalities can function as trapsites, and their crosslinking reactions decrease the k value of materials. Hence, in this study, new solution‐processable copolymers containing both carboxyl and hydrophobic functionalities are synthesized. A fluorophenyl azide (FPA) based UV‐assisted crosslinker is also employed to promote the movement of polar carboxyl groups toward the bulk region and the hydrophobic functionalities to the surface region, thereby maintaining the high‐k characteristics and hydrophobic surface in thin film. Thus, the addition of an FPA crosslinker eliminates the trapsites on the surface, allowing a stable operation and efficient charge transport. Additionally, the solution‐processability enables the production of uniform and thin films to yield OFETs with stable and low‐voltage driving characteristics. The printed layers are also applied as gate dielectrics for floating gate memory devices and in integrated one‐transistor‐one‐transistor based memory cells, displaying their excellent memory performance. The synthesis and fabrication strategies employed in this study can become useful guidelines for the production of high‐k dielectrics for stable OFETs and other applications.

The purpose of this study is to develop novel triazole-containing hydrogels (TGs) as drug carrier and to investigate the sustained drug release accomplished by their time-dependent swelling behavior. The synthetic pathway of TGs includes: (1) DCC-coupling on hydroxyethyl methacrylate (HEMA) to prepare HEMA-alkyne (HA), (2) click-coupling to prepare a triazole-ring-containing monomer (TM), and (3) the synthesis of a series of TGs. The aggregation between triazole rings is found to be responsible for drug release controllability. Rhodamine 6G is studied as a model anticancer drug for release experiments. The effects of pH and temperature on the properties of sustained drug release are also studied.

Mn dissolution resulting from Mn3+ disproportionation in lithium manganese oxide spinel was significantly depressed by a metal-ion-chelating organogel electrolyte.