Aminatul Sobirah Zahari, <br/><br/>
Effect of molecular weight on Piezoelectric properties of electrospun polyvinylidene fluoride blended with cellulose nanocrystals / 
Aminatul Sobirah Zahari 
 - xv, 83 pages :  Illustration ;  30 cm.+  1 CD ROM 
<br/><br/> Faculty of Industrial Sciences and Technology 
<br/><br/>Thesis (Master of Science) -- Universiti Malaysia Pahang – 2022 
<br/><br/>Includes bibliographical references 
<br/><br/> Polyvinylidene fluoride (PVDF) has become widely used as a piezoelectric material in sensors, actuators, filters, and medical equipment. It is in high demand in industries owing to its high-quality features such as high flexibility, low cost, and light weight. PVDF is available in five types of crystalline phases, namely 𝛼, 𝛽, 𝛾, 𝛿 and 𝜀 -phases. All the crystalline phases are built based on the molecular chain conformation of -CH2CF2- in PVDF. Two common crystalline phases found in PVDF are 𝛼 and 𝛽-phases. The 𝛼-phase is easily found in PVDF melt, while the 𝛽-phase is produced via poling and annealing at high pressure. The piezoelectricity is dependent on the 𝛽-phase crystalline structure. Therefore, in order to increase the formation of the 𝛽 -phase, cellulose nanocrystals (CNCs) with various weights (1%-5%) were incorporated into PVDF using the electrospinning method. This method uses high voltage to fabricate electrospun PVDF/CNCs membranes. Analytical methods such as field emission scanning electron microscopy (FESEM), Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction XRD, universal testing machine (UTM), electrochemical impedance spectroscopy (EIS), and a piezoelectric meter were used to evaluate the impact of CNCs on the structural and electrical properties of electrospun PVDF. Based on the FTIR and XRD results, CNCs promoted the development of 𝛽-phase and improved crystallinity up to 75.62%. PVDF with 4% CNCs recorded the highest 𝛽-phase content of up to 91.74% with a maximum piezoelectric constant of 45.0 pC/N and a dielectric constant of 5.4. The mechanical properties of electrospun PVDF/CNCs membranes also improved after incorporating CNCs into PVDF. Therefore, the characteristics of electrospun PVDF/CNCs membranes improved significantly using CNCs. 
<br/><br/><label>ISBN: </label>THE0009451 (Local) 
<br/><br/><label>Subjects--Corporate Names: </label><br/>Faculty of Industrial Sciences and Technology--Dissertations
<br/><br/><label>Subjects--Topical Terms: </label><br/>Universities and colleges--Dissertations<br/>Thesis