(Đồ án hcmute) design and fabrication of conductive alginate based hydrogel and evaluation of their mechanical properties and conductivity

MINISTRY OF EDUCATION AND TRAINING HO CHI MINH CITY UNIVERSITY OF TECHNOLOGY AND EDUCATION FACULTY FOR HIGH QUALITY TRAINING GRADUATION PROJECT MECHANICAL ENGINEERING TECHNOLOGY DESIGN AND FABRICATION OF CONDUCTIVE ALGINATE-BASED HYDROGELS AND EVALUATION OF THEIR MECHANICAL PROPERTIES AND CONDUCTIVITY LECTURER: TRAN VAN TRON, Ph.D STUDENT: KHUONG NGUYEN MINH KHOI VU VAN QUANG LE HONG TRA SKL010121 Ho Chi Minh City, February 2023 HO CHI MINH CITY UNIVERSITY OF TECHNOLOGY AND EDUCATION FACULTY FOR HIGH QUALITY TRAINING GRADUATION PROJECT DESIGN AND FABRICATION OF CONDUCTIVE ALGINATE-BASED HYDROGELS AND EVALUATION OF THEIR MECHANICAL PROPERTIES AND CONDUCTIVITY Student name: Student ID: KHUONG NGUYEN MINH KHOI 18144030 VU VAN QUANG 18144045 LE HONG TRA 18144055 Major: MECHANICAL ENGINEERING TECHNOLOGY Advisor: TRAN VAN TRON, Ph.D Ho Chi Minh City, February 2023 HO CHI MINH CITY UNIVERSITY OF TECHNOLOGY AND EDUCATION FACULTY FOR HIGH QUALITY TRAINING Capstone Project Proposal Student name: Khuong Nguyen Minh Khoi Student name: Vu Van Quang Student ID: 18144030 Student ID: 18144045 Student name: Le Hong Tra Advisor: Ph.D Tran Van Tron Student ID: 18144055   : 0377513584 : 0797724363 : 0358440570 : 0914146826 Title of Capstone Project: Design and fabrication of conductive alginate-based hydrogels and evaluation of their mechanical properties and conductivity Initial materials: - Molecular structure of sodium alginate; - Fabrication process of conductive alginate-based hydrogels via a diffusion method; - Evaluation of mechanical properties of hydrogels via tensile test; - Method of measuring conductivity; Main Content: - A survey on fabrications and applications of conductive hydrogels; - Fabricating various conductive alginate-based hydrogels and determining their mechanical properties and conductivity; - Preparing self-welding hydrogels and determining their lap shear stress; - Applications of the conductive hydrogels in electrical devices; Expected Results - Conductive alginate-based hydrogels; - Report of capstone project; Delivery date: 05/09/2022 Submission date: 01/02/2023 Language: Report: English Oral presentation: English Dean Head of Department Advisor HO CHI MINH CITY UNIVERSITY OF TECHNOLOGY AND EDUCATION FACULTY OF MECHANICAL ENGINEERING CAPSTONE PROJECT EVALUATION FORM (FOR ADVISOR USE ONLY) Title of thesis: Design and fabrication of conductive alginate-based hydrogels and evaluation of their mechanical properties and conductivity Major: Mechanical Engineering Technology Student’s name 01 (SN 01): Khuong Nguyen Minh Khoi Student’s ID: 18144030 Student’s name 02 (SN 02): Vu Van Quang Student’s ID: 18144045 Student’s name 03 (SN 03): Le Hong Tra Student’s ID: 18144055 Advisor: Tran Van Tron Academic Position: Ph.D Committee Number HĐ5 – TT08 Name of Institute: Ho Chi Minh City University of Technology and Education COMMENTS COMMENTS ON ATTITUDE AND BEHAVIOR OF STUDENTS COMMENTS ON RESULTS OF CAPSTONE PROJECT 2.1 Structure of the capstone project 2.2 Main contents 2.3 Results of capstone project 2.4 Capstone strengths and weaknesses EVALUATION No MAX POINT CONTENT Structure of the capstone project 30 Student follows exactly the format for capstone project given by FME 10 The motivation of the project is clearly provided in the thesis 10 10 The NEED of project is clearly showed in the thesis 50 Main contents (demonstration that students have ability to): Apply knowledge of math, engineering, and science 10 15 Analyze and interpret data Design and manufacturing the system, component or process to meet needs Improvement and development in future 15 Use the software and technical tool to solve the problem Real-life applications of capstone project Products of capstone project Total ACHIEVED POINT 10 10 100 CONCLUSIONS  Accept  Reject HCMC, February 18th , 2023 Advisor (Signature and Name) HO CHI MINH CITY UNIVERSITY OF TECHNOLOGY AND EDUCATION FACULTY OF MECHANICAL ENGINEERING CAPSTONE PROJECT EVALUATION FORM (FOR REVIEWER USE ONLY) Title of thesis: Design and fabrication of conductive alginate-based hydrogels and evaluation of their mechanical properties and conductivity Major: Mechanical Engineering Technology Student’ s name 01 (SN 01): Khuong Nguyen Minh Khoi Student’s ID: 18144030 Student’ s name 02 (SN 02): Vu Van Quang Student’s ID: 18144045 Student’ s name 03 (SN 03): Le Hong Tra Student’s ID: 18144055 Reviewer: Truong Nguyen Luan Vu Academic Position: Associate Professor Ph.D Committee number HĐ5 – TT08 2029 Name of Institute: Ho Chi Minh City University of Technology and Education COMMENTS Structure of the capstone project Main contents Results of capstone project Capstone strengths and weaknesses Questions and Suggestions EVALUATION No MAX POINT CONTENT Structure of the capstone project 30 Student follows exactly the format for capstone project given by FME 10 The motivation of the project is clearly provided in the thesis 10 10 The NEED of project is clearly showed in the thesis 50 Main contents (demonstration that students have ability to): Apply knowledge of math, engineering, and science 10 Analyze and interpret data Design and manufacturing the system, component or process to meet needs Improvement and development in future Use the software and technical tool to solve the problem Real-life applications of capstone project Products of capstone project Total ACHIEVED POINT 15 15 10 10 100 CONCLUSIONS  Accept  Reject HCMC, February 18th , 2023 REVIEWER (Signature and Name) ACKNOWLEDGEMENT We have been given the enthusiastic support and assistance of numerous teachers in several topic areas in order for our thesis to produce positive results We would like to convey our sincere appreciation to all of the professors who have made the environment for our learning and research on the subject the best they possibly could We would first like to express our gratitude to the Ho Chi Minh City University of Technology and Education's administration for creating the best studying environment for students Students can study and practice thanks to the tools and resources provided by the school, which helps them learn more quickly and intuitively Second, we would want to express our gratitude to the professors who have taught us over the last four years and the professors in the department of mechanical engineering When we graduate from college, the information that our professors have given will be the best thing we have brought with us Additionally, having that much knowledge aids in the project's successful completion Our graduate project instructor, Dr Tran Van Tron, is the recipient of our third heartfelt thank you We appreciate him because he gave us the ideal conditions to work in while the project was being created We appreciate your support, assistance, and sharing of expertise that helped us finish our graduation project effectively The fourth thank you goes out to our fellow students for supporting and assisting one another throughout the learning process We would especially like to thank our family members who have stood by us, supporting and encouraging our academic endeavors so that we have been able to finish this extremely significant project up to this point The graduating project's thesis has flaws because of our limited time and experience We eagerly await the advice and criticism of the instructors so that we may complete what is still needed We pledge ourselves that we will work harder each day to increase our self-awareness and prepare for the actual task later so that we won't let the professors down We hope you stay well so you can accomplish a lot in your teaching career We sincerely hope you can continue to educate youngsters that excel in the classroom Teachers, thank you for all the lessons you have taught us ABSTRACT Hydrogels are regarded as promising materials that have undergone extensive research recently They have networks of hydrophilic polymers that are crosslinked in three dimensions Alginate-based hydrogels exhibited exceptional properties such as biocompatibility, biodegradability, non-toxic, and eco-friendly, thus they show tremendous potential for applications in biomedical and engineering fields including enhanced wound dressings, bio-ink, and drug delivery vehicles Recently, conductive hydrogels are one of the best candidates for applications of hydrogels, for example flexible electronic devices, sensors, actuators, and soft robotics For matching the requirement in uses, the hydrogels displaying which require functional soft materials with strong mechanical properties and good conductivity In this work, a conductive hydrogel was made, using charcoal (steam activated) which represents a new development for a material with good mechanical properties and high electrical conductivity Additionally, the self-welding ability of the developed hydrogels is also evaluated Conductive hydrogels, with their eco-friendly, high mechanical properties, good electrical conductivity and self-welding ability can be developed for more advanced functions in future studies CONTENTS Capstone Project Proposal CAPSTONE PROJECT EVALUATION FORM CAPSTONE PROJECT EVALUATION FORM ACKNOWLEDGEMENT ABSTRACT CONTENTS LIST OF FIGURES AND CHARTS 11 LIST OF FORMULAS 15 CHAPTER I: INTRODUCTION 16 General introduction of hydrogels 16 Topic importance 17 Aims of this capstone project 17 Research limitations 17 Approaching methods 18 5.1 Approaching methods 18 5.2 Available documents 18 CHAPTER 2: FABRICATING ALGINATE HYDROGELS 19 Principles of hydrogel synthesis 19 Alginate-based hydrogels 24 2.1 Alginate resources 24 2.2 Alginate chemical structure 25 2.3 General properties of alginate 26 2.4 Gelation of alginate 27 Conductive hydrogels and their applications 28 Figure 47 Effect of drying on the mechanical properties of conductive Ca-alginate hydrogels (a) Nominal stress – tensile strain curves recorded at different alginate’s concentrations of weight percent, and the (b) Young’s modulus, (c) tensile strength, and (d) tensile strain, (e) work of extension, and (f) water content determined under each condition 61 2.4 Determining lap shear stress of self-welding hydrogels The Ca-alginate hydrogels used in this study also have a self-welding property that makes them beneficial for a variety of typical applications, including sensors, bioelectrodes, and soft robotics Previous research [26] have described a welding technique based on the ion-induced interfacial reconfiguration of cellulose that can be used to successfully combine cellulose hydrogels Though the ability to "self-weld" can be viewed as a form of "self-healing" because it enables gels to reattach following macroscopic damage, their formation mechanism is a little different The traditional method of self-healing in gels relies mostly on dynamic and reversible noncovalent interactions in the gel network, which can quickly rebuild the broken surfaces without the need for additional materials This substrate is activated, offers the substance to connect the surfaces of the hydrogels It is based on a mixture of weight percent Na-alginate and glycerol 99% Using fillers to bind materials is comparable to the traditional welding method used on metallic components In this study, we demonstrated the versatility of the self-welding method for the Ca-alginate hydrogels We welded samples using [Ca-alginate@C/0.5/5/8] and isotropic [Ca- alginate/0.5/5] The welded samples were easily fabricated (Figure 48) The welding efficiency was quantitatively determined using lap shear testing and the results indicated that the welded samples presented an excellent adhesive strength (>1MPa) (Figure 49, 50) Figure 48 Self-welding hydrogels (a) Self welding prepared via welding of a 30 mm × mm [Ca-alginate@C/0.5/5/8] and isotropic [Ca-alginate/0.5/5], (b) Welded samples using [Ca-alginate@C/0.5/5/8] and isotropic [Ca-alginate/0.5/5] 62 Figure 49 Shear force and corresponding shear stress versus displacement curves obtained via lap shear testing of the welded gels fabricated using only [Caalginate@C/0.5/5/8] Figure 50 Shear force and corresponding shear stress versus displacement curves obtained via lap shear testing of the welded gels fabricated using [Ca-alginate@C/0.5/5/8] and isotropic [Ca-alginate/0.5/5] 63 Self-welding samples have good weld adhesion When performing lap shear stress testing, the hydrogels are only break in the part without the weld (Figure 51) Figure 51 Self-welding samples after lap shear stress testing (a) Welded samples using [Ca-alginate@C/0.5/5/8], (b) Welded samples using [Ca-alginate@C/0.5/5/8] and isotropic [Ca-alginate/0.5/5] 64 CHAPTER 5: CONDUCTIVE Ca-ALGINATE HYDROGELS APPLICATION Main reasons for choosing conductive Ca-alginate hydrogels 1.1 Realistic applications In fact, the range of applications of hydrogels is enormous, which covers various fields such as health, agriculture, life, etc Conductive hydrogels have considered as promising materials to revolutionize flexible electronics, conductors and soft robotics Flexible electronic devices are no longer unfamiliar to the world Compared with traditional inflexible silicon based electronics, flexible electronics satisfiles us excellent mechanical deformation ability, sensitive environment responsiveness and humanmachine interaction effective The emergence and development of sflexible electronic devices brought the challenge to the corresponding devices to meet higher demands for mechanical deformation matching including bending, folding, twisting, and stretching etc Conductive hydrogels have attracted great interest as soft conductors for flexible electronic devices due to their flexibility, high tensile properties and high conductivity can be used to make conductors biodegradable, environmentally friendly Besides, selfwelding ability is also a potential candidate for the application of flexible circuits 1.2 Main reasons for choosing conductive Ca-alginate hydrogels According to data collected from agencies affiliated to the United Nations and governmental and non-governmental organizations worldwide, the amount of waste from electronic components on a global scale is constantly increasing in recent years recent years Waste from electronic components containing heavy metals can be released during inappropriate recycling, resulting in harm to humans, animals, plants or other components of the environment The countries most affected by e-waste recycling are China, India and several African countries (Lagos in Nigeria, Accra in Ghana) where e-waste has been recycled or disposed of with little or no regulation According to the European Environment Agency (EEA), the amount of e-waste generated in the world is about 40 million tons/year and this type of waste grows times faster than other types of waste One of the reasons is that the consumption of this type of product is 65 continuously increasing, especially in populous and fast-growing countries such as China and India Therefore, finding materials that can replace heavy metal in electronic components but not pollute the environment is one of the top urgent issues Conductive hydrogels, an up-to-the-minute class of material, is an environment friendly, non-toxic material because the components that make up conductive hydrogels include alginate extracts extracted from algae combined with non-toxic cations such as Ca2+ Conductive hydrogel with good conductive properties and self-welding ability could be a potential candidate for electronic component manufacturing industry and conductors In addition, the field is developing rapidly thanks to the work of scientists and engineers worldwide from diverse fields Performing applications 2.1 Application 1: Fabrication electrical conductors The manufacture of finished products to serve the above needs, the material must meet the shape and durability Therefore, in the process of considering mechanical properties after improvement We chose free dried [Ca-alginate@C/0.5/5/8] hydrogels for application in these cases due to its suitable mechanical properties To demonstrate the application of making electric conductors, a piece of free dried [Ca-alginate@C/0.5/5/8] hydrogels was prepared using the method described in chapter (Figure 20) We cut two samples of free dried [Ca-alginate@C/0.5/5/8] hydrogels to the dimensions of 30 x mm (length x width) Connect two samples of hydrogels to a power source (25V - 10A) and attach a light emitting diode (LED) to the other end Adjust the voltage gradually from 17V to 25V in turn Lights brighter when voltage is increased and vice versa 66 Figure 52 Croocodie clips creating a temporary electrical connection Figure 53 Pulse source with voltage of 25V 67 Figure 54 Light-emitting diode (LED) illumination using an electrical circuit comprising the [Ca-alginate@C/0.5/5/8] hydrogels, respectively, under an applied voltage of 25 V 2.2 Application 2: Fabrication flexible circuit board Samples of free dried [Ca-alginate@C/0.5/5/8] hydrogels were prepared by the method described in chapter (Figure 20) Then the [Ca-alginate@C/0.5/5/8] hydrogels were cut into different dimensions used for electric conductors Welding samples of [Caalginate@C/0.5/5/8] hydrogels to a substrate based on isotropic [Ca-alginate/0.5/5] hydrogels (with dimensions is 80 x 80 mm) Thanks to the self-soldering ability of hydrogels, we can make a flexible circuit board for flexible electronic devices Figure 55 Diagram of the circuit used for the light-emitting diode (LED) testing The circuit consisted of three resistors 100Ω, one transistor (A1015), and one LED 68 Figure 56 Fabrication flexible electric circuit board (a) A substrate based on isotropic [Ca-alginate/0.5/5] hydrogels (with dimensions is 80 x 80 mm), (b) Welding samples of [Ca-alginate@C/0.5/5/8] hydrogels onto a substrate based on isotropic [Ca-alginate/0.5/5] hydrogels to make a flexible circuit board Figure 57 Flexible electric circuit board (a) Flexible circuit board after bonding Ca2+ fabricated by welding [Ca-alginate@C/0.5/5/8] hydrogels stripes onto the isotropic [Caalginate/0.5/5] hydrogels, (b) Prototype circuit lighting an LED when connected to a power supply with a potential of 55 V 69 CHAPTER 6: CONCLUSIONS In recent years, the research on conductive alginate hydrogels has been explored and deepened Thanks to the documents and research of our predecessors, helped us to have a better overview of alginate hydrogels Their hydrogels synthesis, resources, chemical structure, properties, gelation, and applications of alginate were thoroughly represented Conductive alginate hydrogels were prepared by diffusion method Then, free dried and clamp dried alginate hydrogels were fabricated by structural modification of the initial hydrogels, their mechanical properties were investigated by tensile tests and yielded extremely promising signs of improved mechanical properties and applications they may bring in the future Young's modulus, tensile strength, work of extensions, and tensile strain have values ranging from several times higher, compared to the initial hydrogels The conductivity of hydrogels was also significantly improved by increasing the weight percent concentration of activated carbon Besides, the self-welding ability of hydrogels also opens a new chapter for flexible electronic device applications Practical applications of hydrogels, electric conductors and flexible electric circuit board, which fit the size of the study and the team's budget, have been carried out In the current era, the exciting development of science - engineering in general and specialised in materials in particular has a very important meaning in deciding the development of the world Therefore, in addition to modifying the mechanical properties of alginate hydrogels and evaluating their improvement in mechanical properties, improvements in electrical conductivity, thermal conductivity, and self-healing hydrogels are 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