In this report, a simple solution-cast method was employed to prepare poly(dopamine) (PDA) encapsulated BaTiO (BT) nanoparticle (PDA@BT) filled composites using PVDF matrix cross-linked by the free radical initiator. The effects of both the particle encapsulation and matrix cross-linking on the mechanical and dielectric properties of the composites were carefully investigated. The results suggested that the introduction of BT particles improved permittivity of the composites to ∼30 at 100 Hz when particle contents of only 7 wt % were utilized. This was attributed to the enhanced polarization, which was induced by high permittivity ceramic particles. Compared to bare BT, PDA@BT particles could be dispersed more homogeneously in the matrix, and the catechol groups of PDA layer might form chelation with free ions present in the matrix. The latter might depress the ion conduction loss in the composites. Other results revealed that the formation of hydrogen-bonding between the PDA layer and the polymer, especially the chemical cross-linking across the matrix, resulted in increased Young' modulus by ∼25%, improved breakdown strength by ∼40%, and declined conductivity by nearly 1 order of magnitude when compared to BT filled composites. The composite films filled with PDA@BTs indicated greater energy storage capacities by nearly 190% when compared to the pristine matrix. More importantly, the excellent mechanical performance allowed the composite films to adopt uni- or biaxially stretching, a crucial feature required for the realization of high breakdown strength. This work provided a facile strategy for fabrication of flexible and stretchable dielectric composites with depressed dielectric loss and enhanced energy storage capacity at low filler loadings (<10 wt %).

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In an attempt to determine whether the dose of an antiepileptic drug should be increased in epileptic patients who were seizure-free and had subtherapeutic serum levels, 79 patients with idiopathic generalized tonic-clonic seizures treated with monotherapy [phenytoin (PHT) or phenobarbital (PB)] and with a subtherapeutic serum level were prospectively studied. Their last seizure was at least 3 months prior to entry, and no patient had any clinical evidence of toxicity. They were randomized to study arm A (keeping the level in the subtherapeutic range) or study arm B (increasing the dose until the level reached and stayed at the therapeutic range). Over a mean follow-up period of 24 months, there was no significant difference between the two study arms in the occurrence of seizures, but arm B patients had an increased incidence of neurotoxic side effects from the dose increment. These results confirm the clinical impression that it is unnecessary to increase the dose of the antiepileptic drug despite a subtherapeutic serum concentration in a relatively well-stabilized patient, thus minimizing the frequency of dose adjustment and the need for expensive therapeutic drug monitoring.