Đồ án development of conductive alginate based hydrogels with excellent mechanical properties and conductivity via the reconstruction process

MINISTRY OF EDUCATION AND TRAINING HO CHI MINH CITY UNIVERSITY OF TECHNOLOGY AND EDUCATION FACULTY FOR HIGH QUALITY TRAINING CAPSTONE PROJECT ELECTRONICS AND TELECOMMUNICATIONS ENGINEERING TECHNOLOGY DEVELOPMENT OF CONDUCTIVE ALGINATE-BASED HYDROGELS WITH EXCELENT MECHANICAL PROPERTIES AND CONDUCTIVITY VIA THE RECONSTRUCTION PROCESS LECTURER: PHD TRAN VAN TRON STUDENT: NGUYEN TRAM ANH DOAN THAI BINH NGUYEN LUU MINH THUAN S K L 01 1 Ho Chi Minh City, 2023 MINISTRY OF EDUCATION AND TRAINING HO CHI MINH CITY UNIVERSITY OF TECHNOLOGY AND EDUCATION FACULTY FOR HIGH-QUALITY TRAINING GRADUATION PROJECT Project: “Development of conductive alginate-based hydrogels with excellent mechanical properties and conductivity via the reconstruction process ” Advisor: PhD TRAN VAN TRON Students: NGUYEN TRAM ANH DOAN THAI BINH NGUYEN LUU MINH THUAN Student IDs: 18144003 18144008 18144054 Class: 18144CLA Year: 2018-2022 Ho Chi Minh City, July 2023 HO CHI MINH CITY UNIVERSITY OF TECHNOLOGY AND EDUCATION FACULTY FOR HIGH-QUALITY TRAINING Faculty: Mechanical Engineering GRADUATION PROJECT Project: “ Development of conductive alginate-based hydrogels with excellent mechanical properties and conductivity via the reconstruction process” Advisor: PhD TRAN VAN TRON Student: NGUYEN TRAM ANH DOAN THAI BINH NGUYEN LUU MINH THUAN Student ID: 18144003 18144008 18144054 Class: 18144CLA Year: 2018-2022 Ho Chi Minh City, July 2022 UNIVERSITY OF TECHNOLOGY AND EDUCATION THE SOCIALIST REPUBLIC OF VIETNAM FACULTY OF HIGH-QUALITY TRAINING Independence – Freedom– Happiness GRADUATION PROJECT ASSIGNMENT Semester 2/ Year 2022-2023 Advisor: PhD Tran Van Tron Student’s name: Nguyen Tram Anh Student ID: 18144003 Phone no.: 0352267285 Student’s name: Doan Thai Binh Student ID: 18144008 Phone no.: 0917991974 Student’s name: Nguyen Luu Minh Thuan Student ID: 18144054 Phone no.: 0934862467 Graduation project - Project code: 22223DT83 - Project title: “ Development of conductive alginate-based hydrogels with excellent mechanical properties and conductivity via the reconstruction process” Initial data and documents: - 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; Content of the project: - A survey on fabrications and applications of recently reported conductive hydrogels; - Synthesizing the initial conductive alginate-based hydrogels and developing the reconstruction process for the gels; - Fabricating a series of conductive hydrogels via the developed reconstruction process; - Evaluating their mechanical properties and conductivity; - Preparing self-welding conductive hydrogels and determining their shear stress; i Final product: - Conductive alginate-based hydrogels; - Report of capstone project; Project delivery date: 15/03/2023 Project submission date: 21/07/2023 Presentation language: Report: Presentation: English  Vietnamese  English  Vietnamese  HEAD OF MAJOR ADVISOR  Allowed to protect ii LỜI CAM KẾT - Tên đề tài: “ Phát triển alginate hydrogels dẫn điện với tính và độ dẫn điện vượt trội thông qua quá trình tái cấu trúc” - GVHD: TS Trần Văn Trọn - Họ tên sinh viên 1: Nguyễn Trâm Anh - MSSV: 18144003 - Địa chỉ sinh viên 1: 50/1A, đường Xuyên Á (QL1A), KP Bình Đường 1, phường An Bình, Thành phớ Dĩ An, tỉnh Bình Dương - Sớ điện thoại liên lạc 1: 0352267285 - Email 1: nguyntramanhhh@gmail.com - Họ tên sinh viên 2: Đoàn Thái Bình - MSSV: 18144008 - Địa chỉ sinh viên 2: 189i/15 Tôn Thất Thuyết, phường 3, quận 4, Thành phố Hồ Chí Minh - Số điện thoại liên lạc 2: 0917991974 - Email 2: binhdoanmap@gmail.com - Họ tên sinh viên 3: Nguyễn Lưu Minh Thuận - MSSV: 18144054 - Địa chỉ sinh viên 3: 226/1 đường Nguyễn Văn Lượng, phường 17, quận Gò Vấp, Thành phố Hồ Chí Minh - Số điện thoại liên lạc 3: 0934862467 - Email 3: thuan1382000@gmail.com - Ngày nộp khóa luận tốt nghiệp (ĐATN): - Lời cam kết: “Chúng tơi xin cam đoan khố luận tốt nghiệp (ĐATN) cơng trình chúng tơi nghiên cứu thực Chúng không chép từ viết công bố mà khơng trích dẫn nguồn gốc Nếu có vi phạm nào, chúng tơi xin chịu hồn tồn trách nhiệm” Tp Hờ Chí Minh, ngày tháng … năm 2023 Ký tên iii COMMITMENT - Project’s title:“ Development of conductive alginate-based hydrogels with excellent mechanical properties and conductivity via the reconstruction process” - Advisor: PhD Tran Van Tron - Name of student 1: Nguyen Tram Anh - ID number of student 1: 18144003 - Address of student 1: 50/1A, Xuyen A (QL1A) Street, Binh Duong Town, An Binh Ward, Di An City, Binh Dương Province - Phone number of student 1: 0352267285 - Email of student 1: nguyntramanhhh@gmail.com - Name of student 2: Doan Thai Binh - ID number of student 2: 18144008 - Address of student 2: 189i/15 Ton That Thuyet Street, Ward 3, District 4, Ho Chi Minh City - Phone number of student 2: 0917991974 - Email of student 2: binhdoanmap@gmail.com - Name of student 3: Nguyen Luu Minh Thuan - ID number of student 3: 18144054 - Address of student 3: 226/1 Nguyen Van Luong Street, Ward 17, Go Vap District, Ho Chi Minh City - Phone number of student 3: 0934862467 - Email of student 3: thuan1382000@gmail.com - The deadline for submitting the graduation thesis (ĐATN): - Commitment: “ We hereby solemnly declare that this graduation thesis is the result of our research and implementation We have not copied from any previously published articles without proper citation In case of any violation, we take full responsibility.” Tp Hồ Chí Minh, ngày tháng … năm 2023 Ký tên iv LỜI CẢM ƠN Chúng tơi xin bày tỏ lịng biết ơn chân thành đến Tiến sĩ Trần Văn Trọn hỗ trợ śt q trình thực hiện và hoàn thành đề tài luận văn tốt nghiệp Sự hướng dẫn hỗ trợ từ thầy, việc cung cấp kiến thức cần thiết trang thiết bị vật lý, đóng vai trị quan trọng thành cơng dự án Nhờ hướng dẫn thầy, chúng hoàn thành dự án với kết mong ḿn Chúng tơi ḿn bày tỏ lịng biết ơn đến giảng viên làm việc ở phòng Thí nghiệm Vật liệu tạo điều kiện thuận lợi để nhóm chúng tơi tiến hành thí nghiệm Sự hỗ trợ từ thầy/ cô giúp chúng tiếp cận với thiết bị vật liệu cần thiết để tiến hành thí nghiệm nghiên cứu Ći cùng, chúng tơi ḿn bày tỏ lịng biết ơn đến bạn Lê Hờng Trà thành viên khác nhóm hỗ trợ đờng hành śt trình dự án Sự giúp đỡ bạn giúp chúng vượt qua thách thức và đạt được kết cuối Một lần nữa, chúng tơi xin bày tỏ lịng biết ơn chân thành tới Tiến sĩ Trần Văn Trọn, tất giảng viên thành viên nhóm đóng góp đáng kể vào thành cơng nhóm chúng tơi Sự giúp đỡ hỗ trợ bạn là ng̀n đợng lực to lớn giúp chúng tơi hồn thành dự án Trân trọng, Nguyễn Trâm Anh Đoàn Thái Bình Nguyễn Lưu Minh Thuận v EXPRESSIONS OF GRATITUDE We would like to express our gratitude to Dr Tran Van Tron for assisting us throughout the process of conducting and completing our graduation project The guidance and support provided by Dr Tran Van Tron, as well as the provision of essential knowledge and physical equipment, have been instrumental in our project's success We appreciate Dr Tran Van Tron's willingness to answer our questions and support us during the research and implementation phases Thanks to his guidance, we have successfully completed our project with the desired outcomes We would also like to extend our appreciation to the supervisors in the Materials Science Department for creating favourable conditions for our team to conduct experiments The support from the supervisors has enabled us to have access to the necessary equipment and materials for conducting experiments and research Lastly, we would like to express our gratitude to Ms Le Hong Tra and our fellow team members for their support and companionship throughout the project Your assistance has helped us overcome challenges and achieve the final results Once again, we would like to express our sincere appreciation to Dr Tran Van Tron, all the supervisors, and our team members for their significant contributions to the success of our group Your help and support have been a tremendous source of motivation for us to complete the project Sincerely, Nguyen Tram Anh Doan Thai Binh Nguyen Luu Minh Thuan vi ABSTRACT Development of conductive alginate-based hydrogels with excellent mechanical properties and conductivity via the reconstruction process Hydrogel alginate, as an electrically conductive material, represents a promising and rapidly developing field in materials science and engineering Research and development on hydrogel alginate can lead to significant discoveries regarding its properties and applications, opening up new opportunities for technological advancements and future applications Therefore, our team has decided to undertake a project on the development of alginate-based hydrogels with electrical conductivity The focus of this thesis is on the development of alginate-based hydrogels, a type of polymer derived from seaweed, which exhibits both electrical conductivity and favourable mechanical properties through a restructuring process The research team has conducted detailed studies and achieved impressive results Through experimental investigations and based on the obtained results, the optimal composition and mixing ratios have been determined to create hydrogels with superior electrical conductivity and mechanical properties Importantly, the alginate hydrogel exhibits the ability to self-restructure after deformation, ensuring reliability and durability in practical applications The chosen application for development is the fabrication of electrical circuits Thanks to its good electrical conductivity and the ability to form interconnections between hydrogel joints through self-welding methods, alginate hydrogels can be used to create flexible and stretchable electrical circuits This opens up numerous opportunities for applications in medical fields, electronic technologies, biological monitoring, and measurement devices In summary, this thesis focuses on the development of electrically conductive alginate hydrogels with superior mechanical properties and electrical conductivity through the restructuring process The main application of these hydrogels within the scope of this project is in the fabrication of flexible electrical circuits, offering great potential for applications in the medical and electronic industries The research outcomes hope to contribute to the development and wide-ranging applications of electrically conductive alginate hydrogels Further research can concentrate on process optimization, fine-tuning the properties of the hydrogels, and exploring their diverse applications in the industrial and medical fields vii CHAPTER CHAPTER 5: SELF-WELDING AND APPLICATIONS 5.1 Self- welding After concluding that the selected gel for further development is the gel with wt% alginate and wt% carbon, prepared using process B with a Cu 2+ concentration of 0.01M, as presented in Chapter 4, this chapter will be used to present the self-welding capability of the electrically conductive hydrogel and the application of self-welding joints in flexible circuit fabrication Simply put, the self-welding ability of the electrically conductive hydrogel in this research refers to its capacity to autonomously rejoin separated parts of the hydrogel without external intervention In the case of electrically conductive hydrogel, the self-welding capability allows the separated parts of the hydrogel to be welded back together when physical or electrochemical connections occur This process can be achieved through various mechanisms, such as establishing chemical interactions between polymer chains 5.1.1 The process of manufacturing a self-welding joint a b c d e f g Figure 5.1 Schematic of manufacturing self-welding joint (a) Initial sample (b) Sample after being immersed in NaCl (c) Sample after being washed H2O (d) Sample after being coated Glycerol- Alginate (e) samples attached (f) Joint after being immersed in CaCl2 and (g) Joint after being immersed in CuCl2 52 CHAPTER Firstly, to proceed with the fabrication, the research team prepared gels for the process, specifically a gel type selected in Chapter 4, which at that time was a Cu-Alginate and C matrix structure, exhibiting high mechanical and electrical conductivity (Figure 5.1a) Next, the samples were immersed in NaCl for a period of hours During this stage, Na molecules penetrated the gel surface and attacked the Cu-Alginate bonds, displacing Cu2+ from the bonds and replacing it with Na As Na molecules weakly interacted with Alg fibres, the gel structure became less stable and prone to sliding (Figure 5.1b) At this stage, the structure transformed into Na-Alg Subsequently, the gel was rinsed with water for 45 minutes This step aimed to remove any remaining free Cu molecules and weakly bonded Na molecules, leaving only Alg within the gel structure (Figure 5.1c) Next, glycerol was applied to the gel It is important to note that this process took hours and required continuous scraping of the gel surface and applying a fresh layer of glycerol every 10 minutes During this step, the Alg fibres completely slid away, losing their interconnections (Figure 5.1d) Following that, the research team brought together two gel pieces that had been previously treated with glycerol It can be observed that the Alg fibres on the surface, due to their zigzag structure, would bond weakly with each other (Figure 5.1e) Continuously, the assembled gel pieces were immersed again in a CaCl2 solution for day During this stage, Ca molecules infiltrated the gel surface, penetrating the Alg bonds and forming Ca-Alg bonds This process resulted in the self-healing capability of the gel (Figure 5.1f) After being rinsed with water, the free calcium ions are washed away, leaving only tightly bound calcium molecules within the Ca-Alginate network Finally, the joint is immersed in a CuCl2 solution At this point, the Cu molecules in the solution infiltrate the surface of the Ca-Alginate hydrogel The Cu molecules displace the Ca molecules and replace them in bonding with the Alginate fibres Most of the Ca molecules become free molecules, while some remain within the bonds, adjacent to the Cu molecules This process strengthens the joint compared to the previous step, thanks to the presence of the Cu molecules (Figure 5.1g) 5.1.2 Analysis, evaluation, and results After successfully synthesizing the bond between two individual gel pieces through the self-welding capability of alginate hydrogel, the research team will investigate 53 CHAPTER more in the gel properties which is self-welding In this stage, we will keep the same test as we have done in every previous test To ensure accurate documentation and preserve the integrity of data, meticulous recording procedures will be followed throughout the testing operations due to the fragile nature of the sample after self-welding (Figure 5.2) To minimize the risk of errors or data loss, measurements of shear stress and load force will be logged electronically, allowing for real-time and precise data collection Multiple trials will be conducted to account for any variability in results, facilitating the identification of trends and patterns Figure 5.2 The quality testing process for the self-welded joint (a) Sample Placement, (b) Lowering the Machine, (c) Measurement of Initial Length, (d) Observation of Crack Formation 54 CHAPTER In this stage of the study, the focus will be solely on the shear stress and load force of the Ca-alginate sample with wt% during the self-welding process Other tests previously mentioned will not be conducted at this stage After conducting the testing and obtaining the necessary data, the results will be analyzed using a double-line chart This charting method allows for a visual representation and comparison of the collected data points, facilitating a comprehensive analysis (Figure 5.3) Figure 5.3 Mechanical Properties of the self-welding of sample Ca-alginate with wt% The double-line chart will plot the two sets of data obtained from the self-welding process, specifically the shear stress and load force measurements The x-axis of the chart will represent the relevant displacement, while the y-axis will indicate the corresponding values of shear stress and load force The maximum force observed during the self-welding process is approximately 8N, while the corresponding shear stress reaches around 0.3 MPa By analyzing these values, it indicates that the Ca-alginate sample with wt% C is capable of withstanding significant force and shear stress during the self-welding process The shear stress value of approximately 0.3 MPa further supports the effectiveness of the self-welding process Shear stress refers to the force applied parallel to the surface of the sample, inducing sliding or deformation The observed shear stress indicates that the selfwelding mechanism is successful in creating cohesive bonds within the Ca-alginate gel 55 CHAPTER The combination of the high force and shear stress values suggests that the selfwelded Ca-alginate sample exhibits robust mechanical properties This indicates the potential for the sample to be used in applications requiring strong adhesion or bonding, as it can withstand significant external forces without compromising its structural integrity 5.2 Applications After successfully applying the self-welding capability of alginate hydrogels, the research team will proceed to fabricate electrical circuits from the flexible connections created in the previous step 5.2.1 Preparation and design The research team's idea is to leverage the self-welding ability of alginate hydrogel to create a flexible and simple circuit system They will incorporate electronic components including three resistors, one NPN transistor, a 2V LED bulb and a power source adjusted to 55V The key difference in this electrical circuit is that instead of using wires to conduct electricity, the conducting tool here is the self-welding joint mentioned and fabricated in section 5.1 This approach aims to demonstrate the potential of alginate hydrogel as a promising alternative to existing conductive materials on the market Figure 5.4.Wiring diagram of flexible circuit The research team has designed a simple circuit with a width of (mm) for the connections, and the length of the connections is depicted in Figure 5.4 56 CHAPTER 5.2.2 Fabricating flexible electrical circuits After obtaining the assembly diagram, the research team proceeds with the steps to create a flexible electrical circuit a b Figure 5.5 The base plate before and after performing self-welding to create an electrical circuit (a) The base plate before performing self-welding has dimensions of 90 (mm) × 70 (mm) × (mm) (b) The base plate and the joints after performing self-welding Firstly, based on the circuit diagram, the research team will attach the connections onto a base sheet, which is also made of the selected gel but with a concentration of wt% alginate and wt% carbon (Figure 5.5a) Leveraging the self-welding capability of alginate hydrogel, the connections will firmly adhere to the base sheet without the need for any additional adhesive After completing the self-welding process, a simple and flexible circuit board will be obtained (Figure 5.5b) Figure 5.6 The circuit after immersing it in the solution containing Ca2+ ions 57 CHAPTER Next, the research team immersed the entire circuit into a solution containing Ca2+ ions to allow the entire circuit to reform according to the principles explained in section 5.1 The final result was a simple circuit with outstanding flexibility (Figure 5.6) Figure 5.7 The circuit after being immersed CuCl2 solution Next, the research team will immerse the circuit in a CuCl2 solution with a concentration of 0.1 M in order to increase the hardness and durability of the entire circuit (Figure 5.7) Figure 5.8 The circuit after the electronic components have been installed The final step is to test whether this circuit board functions smoothly under reallife conditions To evaluate the sample's electrical conductivity, a simple circuit will be 58 CHAPTER constructed, consisting of components such as one transistor, three resistors, one LED light, and a power source adjusted to 55V (Figure 5.8) 5.2.3 Results and conclusions The purpose of this electrical circuit is to measure the conductivity of the selfwelded sample when subjected to an electrical current By incorporating the sample into the circuit, researchers can observe how it behaves in terms of conducting electricity and whether any improvements in conductivity are achieved through the self-welding process During the testing process, the electrical current passing through the circuit will be monitored, and the behaviour of the LED light will be observed The LED light serves as an indicator of whether the self-welded Ca-alginate sample is capable of transmitting electrical current and producing visible light After completing the circuit, the research team proceeded to power it up The result was that the LED light installed in the circuit illuminated clearly and remained stable (Figure 5.9) This leads to a clear conclusion that the electric circuit with conductive alginate hydrogel as a material can function well and remain stable Figure 5.9 The circuit after being powered up Although the testing can be considered successful, during the experimental process, the research team has identified several points that require discussion Firstly, although the LED light emitted illumination, it was of low power, indicating a limited practical application Secondly, the current supplied to the circuit was approximately 55V, 59 CHAPTER requiring the use of voltage regulators, which caused inconvenience Considering these two points along with the results of the experiment, the research team concludes that alginate hydrogel as a conductive material is a viable option for replacing traditional conductive materials in certain potential fields such as medicine and electronics However, further research and experimentation are needed to improve the electrical conductivity of alginate hydrogel and evaluate its compatibility with household power sources 60 CHAPTER CHAPTER 6: CONCLUSIONS 6.1 Summary The aim of this thesis is to investigate and develop alginate-based hydrogels, which are polymers derived from seaweed, with a specific focus on achieving electrical conductivity and desirable mechanical properties through a restructuring process Through experimental methods, analysis, and comparison, the research team has successfully determined the optimal composition for alginate-based hydrogel with superior mechanical properties and electrical conductivity, which is a mixture of wt% alginate and wt% carbon The hydrogel was produced using the DriedRT/Na/Ca/Cu method with a Cu2+ concentration of 0.01 M Furthermore, the research team has successfully applied these results along with the self-welding ability of alginate hydrogel to create flexible electrical circuits with excellent conductivity and flexibility 6.2 Dicussions Strengths: The research team has successfully accomplished the assigned tasks We have developed a suitable methodology through a process of research, experimentation, comparison, analysis, and iterative refinement This has led to the identification of an optimal approach and its practical application Weaknesses: The research team faced limitations in implementing more effective processes, methods, and applications due to constraints in terms of time, knowledge, and budget 6.3 Recommendations Further research efforts should focus on optimizing the manufacturing process of hydrogels, refining their properties, and exploring their wide range of applications in industries 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