Fabrication and characterization of thermo-responsive GO nanosheets with controllable grafting of poly(hexadecyl acrylate) chains

A series of novel poly(hexadecyl acrylate)-grafted-graphene oxides (PHDA-g-GOs) were fabricated as thermo-responsive GO nanosheets via diazonium addition and surface-initiated atom transfer radical polymerization (SI-ATRP). Various spectroscopic and microscopic evidences confirm the successful fabrication of the thermo-responsive GO nanosheets. The thermo-responsive property and thermal stability of the PHDA-g-GOs were determined by DSC and TGA. Furthermore, we have demonstrated the ability to systematically tune the chain length of polymer molecules covalently bonded to GO nanosheets by SI-ATRP. Comparing the thermo-responsive GO samples, the ∆H_m and ∆H_c increased as the molar ratio of monomer to initiator increased. Moreover, the T_mo, T_co, ∆H_m and ∆H_c values of the PHDA-g-GO3 (with a molar ratio of monomer to initiator as 1000:1) are 31.2, 31.4 °C, 79 and 76 J/g, respectively. Meanwhile, the thermo-responsive GO nanosheets have good thermal stability and shape stability. Therefore, the thermo-responsive GO nanosheet is a very promising functional material and can be used in more areas, such as the fabrication of temperature-sensitive drugs, reagents, fibers and textiles, solar energy storage and temperature sensor.