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Dielectric elastomer (DE) actuators have been shown to have promising applications as soft electromechanical transducers in many emerging technologies. The DE actuators, which are capable of large actuation strain over a wide range of excitation frequencies, are highly desirable. Here, the first single-component DE of a triblock copolymer with attractive electromechanical performance is reported. Symmetric poly(styrene-b-butyl acrylate-b-styrene) (SBAS) is designed and synthesized. The SBAS actuator exhibits about 100% static actuation area strain and excellent dynamic performance, as evidenced by a wide half bandwidth of 300 Hz and a very high specific power of 1.2 W g -1 within the excitation frequency range of 300-800 Hz., (© 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Stimuli-responsive materials with sophisticated yet controllable shape-changing behaviors are highly desirable for real-world device applications. Among various shape-changing materials, the elastic nature of shape memory polymers allows fixation of temporary shapes that can recover on demand, whereas polymers with exchangeable bonds can undergo permanent shape change via plasticity. We integrate the elasticity and plasticity into a single polymer network. Rational molecular design allows these two opposite behaviors to be realized at different temperature ranges without any overlap. By exploring the cumulative nature of the plasticity, we demonstrate easy manipulation of highly complex shapes that is otherwise extremely challenging. The dynamic shape-changing behavior paves a new way for fabricating geometrically complex multifunctional devices.

The chain sequence of a poly(styrene-co-methyl acrylate) copolymer is designed to form a V-shaped gradient sequence via controlled/living radical emulsion copolymerization. This specially designed chain sequence gives this common copolymer the capacity of multishape memory. The copolymer can sequentially recover to its permanent shape from three or more previously programmed temporary shapes with the stimulus of temperature., (Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Supramolecular bonds have been widely used for designing polymers because of their reversible nature. In contrast, utilization of their dynamic equilibrium nature to access materials of unusual mechanical properties has been poorly explored. Taking full advantage of this latter attribute requires the design of polymer networks with high contents of supramolecular bonds. In this work, polymer networks with high contents of self-complementary hydrogen bonds (ureidopyrimidinone) are synthesized using thiol-acrylate click addition. The excellent tunability of the network allows a range of intriguing mechanical properties to be achieved including the transition from plasticity to elasticity, ultrasoft shape memory polymer, strong strain rate dependence, and high mechanical damping. Materials with such versatile dynamic behaviors may open up a range of new applications. [ABSTRACT FROM AUTHOR]

ABSTRACT The mechanical properties of linear and V-shaped compositional gradient copolymer of styrene and n-butyl acrylate with composition of around 55 wt % styrene were investigated by comparing with their block copolymer counterparts. Compared with their block copolymer counterparts, the gradient copolymers showed lower elastic modulus, much larger elongation at break, and similar ultimate tensile strength at room temperature. This performance could be ascribed to that the local moduli continuously change from the hardest nanodomains to the softest nanodomains in the gradient copolymer, which alleviates the stress concentration during tensile test. Compared with the V-shaped gradient (VG) copolymer, the linear gradient copolymer showed much higher elastic modulus but lower elongation at break. The mechanical properties of the gradient copolymers were more sensitive to the change in temperature from 9 °C to 75 °C. With recovery temperature increased from 10 °C to 60 °C, the strain recovery of VG copolymer would change steadily from 40% to 99%. However, the elastic recovery of linear and triblock copolymer was poor even at 60 °C. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2015, 53, 860-868 [ABSTRACT FROM AUTHOR]

Presents a study that investigated the hybrid systems of acrylic components as they undergo miniemulsion free radical polymerization in the presence of unsaturated alkyd resins. Background on polymerization; Compatibility of the monomer and resinous components; Interaction between the growing polymer and resin.

Dielectric elastomers (DEs) are able to deform significantly in response under an external electric field. DE actuators have promising applications in many emerging fields such as biomimetic robots, haptic devices, tunable lens, and loudspeakers. Practical applications of DE devices are limited by the extremely high electric field and the high pre-stretch. Herein, we have designed and fabricated a new type of soft DE composites of partially reduced graphene oxide (RGO)/polystyrene-b-poly (n-butyl acrylate)-b-polystyrene triblock copolymer (SBAS). An extremely soft SBAS was tailor-made as the elastic matrix. A facile colloidal blending method, i.e. simply mixing the SBAS latex with GO aqueous dispersion, was used to fabricate the nano-structured composite with a segregated network of RGO nano-sheets. The design strategy led to the DE composite film of 1.5 wt% RGO/SBAS owning low modulus (0.51 MPa), high relative permittivity (∼11) and relatively high dielectric breakdown strength (33 kV/mm). The DE composite film exhibited 21.3% maximum area actuation strain at relatively low electric field strength 33 kV/mm without pre-stretch. [ABSTRACT FROM AUTHOR]

[Display omitted] • Successfully prepared a raspberry-inspired micro-size polymer (RMP) binder. • Excellent adhesion and spherical shape-retention capability at high temperature. • Adjustable raspberry-like structure through changing synthesis conditions. • Improved electrochemical performance of batteries by the RMP binder. Surface coating with binders and ceramic particles is one of the most effective strategies to enhance thermal stability and electrolyte wettability of polyolefin separators, yet is still challenged by the issue of hole blocking and contradiction between adhesion and thermostability of binders. Herein, a raspberry-like micro-size polymer (RMP) binder with a soft core inside and hard spheres outside was prepared through seed swelling polymerization. The micron size helps RMP binder to effectively bond separator and electrode, solving the pore blocking problem encountered with traditional liner binders. The raspberry-like structure combines softness and rigidity, ensuring both high spherical shape-retention capability and good binding strength. The ceramic separator with RMP binder shows low thermal shrinkage and high ionic conductivity, achieving high cycling stability and low impedance of the batteries. This work provides new inspiration to construct novel binders for ceramic-coated separators with long-term stability for high-performance lithium-ion batteries. [ABSTRACT FROM AUTHOR]