Electroactive poly(vinylidene fluoride-trifluoroethylene)/graphene composites for cardiac tissue engineering applications

Electroactive materials are increasingly being used in strategies to regenerate cardiac tissue. These materials, particularly those with electrical conductivity, are used to actively recreate the electromechanical nature of the cardiac tissue. In the present work, we describe a novel combination of poly(vinylidene fluoride-trifluoroethylene) (P(VDF-TrFE)), a highly electroactive polymer, with graphene (G), exhibiting high electrical conductivity. G/P(VDF-TrFE) films have been characterized in terms of topographical, physico-chemical, mechanical, electrical, and thermal properties, and studied the response of cardiomyocytes adhering to them. The results indicate that the crystallinity and the wettability of the composites remain almost unaffected after G incorporation. In turn, surface roughness, Young modulus, and electric properties are higher in G/P(VDF-TrFE). Finally, the composites are highly biocompatible and able to support cardiomyocyte adhesion and proliferation, particularly surface treated ones, demonstrating the suitability of these materials for cardiac tissue engineering applications.

Designing Micro Bulge Structure with Uniform PS Microspheres for Boosted Dielectric Hydrophobic Blend Films

In this paper, homogeneous polystyrene (PS) microspheres with controllable sizes of 40 nm, 80 nm, and 120 nm were synthesized by controlling the temperature of solvothermal method. In order to explore the effect of PS microspheres on dielectric-hydrophobic properties of the composite films, the composite films containing polystyrene, Polydimethylsiloxane, and P(VDF-TrFE) with high dielectric and hydrophobicity were successfully prepared by a simple and feasible solution blending method. The dielectric constant and hydrophobicity of composite films were boosted by increasing the mass fraction of PS content and decreasing the size of PS due to the enhanced interfacial polarization and the uniform surface micro bulge structure. Meanwhile, the composite films maintain a low loss tangent. Typically, the dielectric constant with 5 wt.% 40 nm PS reached to 29 at 100Hz, which is 4 times that of PDMS/P(VDF-TrFE) (mass ratio: 2/3). Otherwise, the largest the contact angle of 126° in the same composition was remarkably larger than the pure PDMS/P(VDF-TrFE) (110°). These improved properties have more potential applications in the electric wetting devices.

Ferroelectric relaxation dependence of poly(vinylidene fluoride-co-trifluoroethylene) on frequency and temperature after grafting with poly(methyl methacrylate)

By monitoring the D–E curves of P(VDF-TrFE-CTFE)-g-PMMAs at different frequency and temperature, the dependence of the ferroelectric relaxation of grafted copolymers onto testing conditions and composition has been finely illustrated.

Enhance the pyroelectricity of polyvinylidene fluoride by graphene-oxide doping

The high quality properties and benefits of graphene-oxide have generated an active area of research where many investigations have shown potential applications in various technological fields. This paper proposes a methodology for enhancing the pyro-electricity of PVDF by graphene-oxide doping. The PVDF film with graphene-oxide is prepared by the sol-gel method. Firstly, PVDF and graphene-oxide powders are dispersed into dimethylformamide as solvent to form a sol solution. Secondly, the sol solution is deposited on a flexible ITO/PET substrate by spin-coating. Thirdly, the particles in the sol solution are polymerized through baking off the solvent to produce a gel in a state of a continuous network of PVDF and graphene-oxide. The final annealing process pyrolyzes the gel and form a β-phase PVDF film with graphene-oxide doping. A complete study on the process of the graphene oxide doping of PVDF is accomplished. Some key points about the process are addressed based on experiments. The solutions to some key issues are found in this work, such as the porosity of film, the annealing temperature limitation by the use of flexible PET substrate, and the concentrations of PVDF and graphene-oxide.