Abstract. Wettability has been recognized as one of the most important properties of fibrous materials for both fundamental and practical applications. In this study, the plasma induced grafting of acrylic acid (AAc) was applied to improve the wettability of the electrospun poly(vinylidene fluoride) (PVDF) nanofiber membranes. The diameter and chemical structure of the modified PVDF nanofibers were characterized by scanning electron microscopy (SEM) and Fourier transform infrared (FTIR). Nitrogen adsorption based on BET (Brunauer, Emmett and Teller) principle was employed to measure the specific surface areas and porosities of the modified nanofiber membrances. The contact angles of the modified membrane were evaluated by drop shape analysis (DSA) and the modified Washburn method. The dependence of contact angles on specific surface area and porosity was also discussed in this paper. Water adsorptions were used to evaluate the dynamic wetting behavior of the grafted membranes by a dynamic adsorption apparatus (CDCA100-F). The experimental results revealed that the wettablity of the modified PVDF membrane was significantly affected by both surface and porous contact angles.

We have electropolymerized 1,1 from CH3CN, tetrahydrofuran (THF), and CH5CI5 to form an alternating main chain polymer of diphenylbenzidine and ferrocene. As a comparison, we have electropolymerized 1,4 which lacks the electrochemical response of the ferrocene group. In nonaqueous solvents, the diphenylbenzidine group shows two reversible 1e oxidations. The second 1e oxidation of the diphenylbenzidine overlaps with the 1e oxidation of the ferrocene group at 0.88 V vs. Ag/AgCl in CH,C12. The electrochemistry of the polymer film in aqueous acid shows two 1e waves consistent with oxidation of the diphenylbenzidine group to the cation and then the dication. The spectroelectrochemsitry of both polymer films show broad, lowenergy, near-IR bands in aprotic solvents such as CH5C12, THF, and CH3CN and aqueous solutions with pH < 3. We assign these bands to intermolecular it stacking of the protonated diphenylbenzidinium cations. The electrochemistry of both materials is chemically reversible and forms the basis for electrochromic and redox applications.Ferrocene has many interesting properties related to its chemical and electrochemical reversibility, unusual protonation, and electrophilic substitution. Polymers in which ferrocene units are either in the main chain or in the side chains have been synthesized and studied extensively.1 The reversibility of this redox couple makes these systems ideal for chemically based device applications where long-term stability is important. Ferrocene-polymer-based modified electrodes have been extensively studied.2'3 Peerce and Bard reported that poly(vinylferrocene)-coated platinum electrodes can be used as a reference electrode in acetonitrile.4 This has been proposed as a standard reference electrode for nonaqueous electrochemical systems. Hickman et al.5 used a ferrocene-based polymer as an internal reference on a microelectrode array and showed that a voltammetric microsensor can have the reference and the sensor fimctions on the same "chip." Electrodes modified with ferrocene-based compounds have been suggested for biosensor applications.5 The ferrocene-modified enzyme electrode can determine the glucose concentration with ferrocene mediating the electron transfer.7' Ferrocene polymers have been used in the photoelectrochemical reduction of halocarbons and in solar applications." Self-assembled monolayers with ferrocene termini have helped elucidate the nature of charge transfer at interfaces.'2'4 Ferrocenebased charge-transfer complexes have been reported for applications requiring only moderate conductivity15 Conjugated conducting polymers based on ferrocene have been reported.'6'17 Ferrocene has been used as one component of ferromagnetic organic materials and as a group in secondorder, nonlinear optical materials. '8'19 Recently, our group has been interested in studying polymers with the structural motif of (-R-X-R-),,, where R is the polymerizable end group.2' X can be electroactive and can have a different set of redox and optical properties than R. The monomers are eas...