마이크로/나노구조 고분자 메타물질

학위논문 (박사)-- 서울대학교 대학원 : 공과대학 재료공학부, 2018. 8. 윤재륜.Metamaterials are artificially designed and engineered materials to capture the human imagination. Based on mathematical and physicochemical knowledge, manifold metamaterials have been designed with sophisticated polymeric micro/nanostructures. In general, metamaterial design is accomplished by employing micro/nanoscale unit cells that bring out effective media for complex material properties. The metamaterials have been produced as practical devices and have embodied unprecedented phenomena that do not follow the laws of nature. In this dissertation, three classes of metamaterials are proposed by strategic design, numerical analysis, chemical synthesis, fabrication, and experimental characterizationsAbstract i List of Figures viii List of Tables xx Chapter 1. Introduction 1 1.1. What is a metamaterial? 1 1.2. Research background 4 1.2.1. Transformation optics 4 1.2.2. Shape memory polymer 11 1.2.3. Sound absorption 17 1.3. Objectives of present work 22 Chapter 2. Polymeric Rheological Metamaterials 23 2.1. Overview 23 2.2. Transformation rheology 25 2.2.1. Introduction 25 2.2.2. Theoretical background 27 2.2.3. Form invariance of Navier-Stokes equations 32 2.2.4. Conclusions 39 2.3. Rheological cloak 40 2.3.1. Introduction 40 2.3.2. Fluidic space modeling 42 2.3.3. Numerical analysis 49 2.3.4. Metamaterial design 58 2.3.5. Experimental realization 73 2.3.6. Conclusions 83 2.4. Rheological concentrator 84 2.4.1. Introduction 84 2.4.2. Fluidic space modeling 86 2.4.3. Numerical analysis 90 2.4.4. Metamaterial design 96 2.4.5. Experimental realization 107 2.4.6. Conclusions 112 2.5. Rheological rotator 113 2.5.1. Introduction 113 2.5.2. Fluidic space modeling 115 2.5.3. Numerical analysis 118 2.5.4. Metamaterial design 123 2.5.5. Experimental realization 134 2.5.6. Conclusions 139 2.6. Summary 140 Chapter 3. Shape Memory Polymeric Metasurfaces 141 3.1. Overview 141 3.2. Shape memory polymer synthesis 143 3.2.1. Introduction 143 3.2.2. Experimental 145 3.2.3. Numerical analysis 148 3.2.4. Results and discussion 154 3.2.5. Conclusions 168 3.3. Antireflective SMP nanopattern 169 3.3.1. Introduction 169 3.3.2. Experimental 171 3.3.3. Numerical analysis 174 3.3.4. Results and discussion 177 3.3.5. Conclusions 191 3.4. Biometric SMP nanopattern 192 3.4.1. Introduction 192 3.4.2. Experimental 194 3.4.3. Numerical analysis 196 3.4.4. Results and discussion 198 3.4.5. Conclusions 213 3.5. Summary 214 Chapter 4. Polymeric Poroacoustic Meta-absorbers 215 4.1. Overview 215 4.2. PU foam with optimum cell size 217 4.2.1. Introduction 217 4.2.2. Experimental 220 4.2.3. Numerical analysis 222 4.2.4. Results and discussion 228 4.2.5. Conclusions 245 4.3. Openness-modulated PU foam 246 4.3.1. Introduction 246 4.3.2. Experimental 249 4.3.3. Numerical analysis 250 4.3.4. Results and discussion 252 4.3.5. Conclusions 268 4.4. Hybrid microstructured PU foam 269 4.4.1. Introduction 269 4.4.2. Design of syntactic hybrid foams 271 4.4.3. Numerical analysis 274 4.4.4. Results and discussion 276 4.4.5. Conclusions 286 4.5. Summary 287 Chapter 5. Concluding Remarks 288 Bibliography 291 Korean Abstract 325Docto