**2. Experimental section**

Ear prostheses (which in common parlance are called "artificial ear") are an example of progress in this area. They are commonly used in patients with microtia, which is a congen‐ ital malformation characterized by the underdevelopment of an ear or two and which is

**•** Grade I is a slightly small ear with identifiable structures and a small but present exter‐

**•** Grade II is a partially formed ear, usually with a closed off or stenotic external ear canal

**•** Grade III is the absence of the external ear with a small "peanut" skin and cartilage

In addition to the psychologic effect of a grossly deformed ear, the child or adult with mi‐ crotia has moderate to severe conductive hearing loss. Although those patients have a nor‐ mal inner ear, it is frequently observed an absence of the external ear (or pinna), an absent external canal and ear drum as well as a smaller middle ear cavity, fused middle ear bones (ossicles), and an open (patent) eustachian tube. Therefore, these patients have a maximum conductive hearing loss. Because it is critical for these patients to have normal hearing in order to have normal speech and bilateral hearing in order to detect directionality, ear prostheses have become the most recommendable alternative, allowing the patient to re‐

This chapter will present the results including the stages of design, fabrication, and charac‐ terization of a 3D-printed ear prosthesis using PVDF, a polymeric smart material which is used as either a sensor or a transducer due to its high piezoelectric, pyroelectric, photo‐

PVDF is the most significant and studied polymer by Lovinger, "Ferroelectric Polymers" in *Science*, 1983 [7] and Gallantree "Review of transducer applications of polyvinylidene fluo‐ ride" 1983 [3]; PVDF responds to pressure (piezoelectric effect), temperature, sound, light, and even moisture (reported by our group), "System for Controlling Moisture of the Soil Using Humidity Sensors from a Polyvinylidene fluoride Fiber mats" [8]. Other polymeric materials which are not pure and exhibit these properties are ZnO/PVDF with graphene for pressure and temperature sensing, described by Lee et al. 2015 [5] or the compounds mentioned in **Table 3** "Comparison of piezoelectric properties of some semicrystalline pol‐

The prosthesis was subjected to pressure, temperature, light, and acoustic stimuli. Thus, the response of these stimuli is presented. This way it is expected to restore sensory func‐ tion, giving the user the ability to perceive heat, cold, touch, and pressure ae did before as

structure and the absence of the external ear canal and ear drum.

cover both functionality and appearance of a natural ear [1].

usually broken down into four categories:

producing a conductive hearing loss.

**•** Grade IV is absence of the total ear (anotia).

pyroelectric, and ferroelectric properties [2–6].

ymeric material" in *Piezoelectric Polymers*, 2001 [9].

well as acoustic waves and light.

nal ear canal.

144 Piezoelectric Materials
