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- Atomic layer deposition (ALD) (2)
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Course of studies
Parylene-C is used for various biomedical devices because of its high conformity and biocompatibility. However, delamination could occur because of low adhesion between Parylene-C and other materials. For this experiment 4-inch Si-wafers are used. Parylene is deposited by chemical vapour deposition (CVD). Silane A-174 as adhesion promoter is added between Parylene-Parylene layers. The samples are soaked at different duration 1 h, 24 h and 120 h in PBS solution at 37 °C. A peel test is further performed to investigate the adhesion properties of the samples.
Passivated electrode side walls by atomic layer deposition on flexible polyimide based samples
(2020)
In the present work, polyetheretherketone (PEEK) was pretreated with oxygen plasma to investigate the influence on the contact angle and surface energy. For this purpose, PEEK samples were fabricated over several manufacturing steps, which were used as substrates for later investigations. A series of measurements was performed at a power of 300 W for different treatment durations and the contact angle of H2O on the PEEK surface was determined. The results show that plasma pretreatment significantly affects the surface modification of PEEK disks. The best hydrophilic properties of the PEEK surfaces were measured at a treatment time of 540 s and a power of 300 W. A much longer treatment time caused the correlated values of contact angle and surface energy to increase and in this case an excessive treatment time did not contribute to a further increase in hydrophilicity.
Investigation on adhesion strength of Parylene-C coatings with different adhesion promotion methods
(2021)
Delamination of encapsulation materials (here the polymer Parylene-C) is one of the biggest failure mechanisms for active medical implants. This problem is addressed by the application of different pre-treatment and adhesion promotion methods. The methods applied in this research are oxygen and Silane A-174 solution pre-treatment and Silane A-174, titanium oxide and Trimethylsilane as adhesion promoters. The adhesion forces of these methods are quantified after different soaking times in phosphate buffered saline (PBS) solution to mimic environment of the human body.