Search

Well-shaped sulfated titania nanofibers were prepared by impregnation of hydrogen titanate with (NH4)2S2O8 and calcination. Various characterization results showed that sulfated titania nanofibers consisted of smooth-surface and long-size fibers with the diameter of dozens of nanometers. Moreover, acid characteristics of sulfated titania nanofibers exhibited the high acid content, multi-strength acid sites and large Brønsted/Lewis acid ratio. In low-viscosity esterification, sulfated titania nanofibers had 1.2 ~ 2.1 times the reaction rate of other sulfated titania and other typical solid acids. Simultaneously, sulfated titania nanofibers possessed the higher DS value of product than those by other solid acids in highly viscous cellulose acetylation (2.41 versus 2.06 ~ 2.21). Besides these, sulfated titania nanofibers could show the excellent recycling performance in viscous acid-catalytic reactions. [ABSTRACT FROM AUTHOR]

Low-voltage soft actuators with large displacement, long actuation durability, and fast response time have aroused great attention in soft robotics, wearable devices, haptic devices, and implantable or disposal biomedical devices. Herein, we report a low-voltage electroactive ionic soft actuator based on the sulfonated cellulose nanowhisker (SCN), microfibrillated cellulose (MFC), ionic liquids (IL), and graphene nanoplatelet (GN). The proposed SCN/MFC-IL-GN (0.1wt%) actuator demonstrated a large bending displacement (6.6 mm under ± 1 V sinusoidal input signal at 0.1 Hz, low driving voltage (as low as 0.25 V), wide actuation frequency (0.1 to 5.0 Hz), and long actuation durability (96.7% retention for 1 h), all of which stemmed from the strong crosslinking and ionic interactions among the functional sulfonated groups of SCN, hydroxyl groups of MFC, IL, and GN. Furthermore, the designed actuator was successfully employed to imitate the human finger's behaviors including turning on/off the flashlight and sliding electronic photographs on a smart phone screen. Therefore, the proposed SCN/MFC-IL-GN actuator has great potential in artificial muscles, soft robots, haptic devices, and wearable devices because of its low excitation voltage, large bending displacement, long actuation durability, and biofriendly property. [ABSTRACT FROM AUTHOR]