Aqueous electrophoretic deposition of bulk polyether ether ketone (PEEK)

• First report on aqueous electrophoretic deposition of bulk polyether ether ketone.
• Effective hydrophilisation of the PEEK particles with a highly negative ζ.
• Formation of self-standing (>1 cm) PEEK deposits with 55%TD density by EPD.
• Ionic conductivity and ion migration effect the formation of deposit.

Aqueous electrophoretic deposition (EPD) is a colloidal processing technique which enables fast formation of bulk deposits. The addition of suitable surfactant would enable dispersion, and due to their effect on electrokinetic properties, also the deposition of hydrophobic particles of polyether ether ketone (PEEK). The electrophoretic properties and the conductivities of suspensions were analysed as a function of the addition of surfactants or the pH, and related to the properties of the as-prepared bulk deposits. A more in-depth understanding of the deposition process was achieved by monitoring the suspensions’ properties (pH, ζ and conductivity) before and after the deposition and observation of the deposits’ properties. We have shown that by using a concentrated suspension of PEEK (50 wt.%) with the addition of DBSA at pH > 4, thick deposits (>15 mm) were formed at moderate voltages (10–30 V cm−1) in 1 min. Although the PEEK polymer is hydrophobic by nature, aqueous EPD was shown to be an effective technique for shaping bulk parts. During the deposition unusual current increase was observed and was attributed to an increase in the conductivity due to the migration of ions and electrochemical reactions at the electrodes.

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