미세 구조 설계를 통한 고분자 복합재의 전자기 간섭 차폐 성능 향상 및 응용

다국어 초록 (Multilingual Abstract)

Lightweight, absorption-effective EMI shielding is pursued here by engineering oriented, porous filler architectures in polymers. In the first study, non-oxidized graphene flakes (NOGF) were blended with PVDF and processed as either hot-pressed, non-oriented bulk or unidirectionally freeze-cast foams at 10 wt% filler and fixed solution volume (total mass 3–6 g). X-band results were benchmarked using total shielding effectiveness (SET), specific SE (SSE, dB·cm³/g), thickness-normalized specific SE (SSE/t, dB·cm²/g), and reflection– transmission–absorption power coefficients. Among foams, the 4g- Foam was optimal, reaching SSE 96.33 dB·cm³/g and SSE/t 511.03 dB·cm²/g; at the same mass it outperformed the non-oriented 4g-Bulk by ~5.15 times in both SSE and SSE/t while keeping transmission below 0.5% and tripling the absorption share (A ≈ 0.25 vs 0.08). These gains stem from improved impedance matching due to porosity and elongated EM paths with internal scattering/multiple reflections inside oriented channels. In the second study, Ti₃C₂Tₓ MXene/PDMS composites were designed to exploit anisotropy. During MILD (LiF/HCl) synthesis, gentle arm-shaker delamination preserved larger flakes and minimized Al-impurity signatures compared with ultrasonication; inert annealing at 500 °C hydrophobized MXene surfaces without structural loss and enabled stable PDMS infiltration, whereas 700 °C caused oxidation. Orientation from freestanding, unidirectionally freeze-cast MXene aerogels was retained after infiltration. Longitudinal specimens (ML) exhibited ~2.2 times higher SER and ~180.7 times higher SEA than transverse (MT), yielding ~397.2 times higher SET; the reflection power coefficient increased from 0.71 (MT) to 0.87 (ML), and electrical conductivity was ~2.77 times higher, consistent with more continuous conductive pathways and longer effective propagation paths. Together, these results show that mild delamination, 500 °C inert annealing, and oriented porous networks maximize SSE/SSE/t while enabling direction-dependent performance.

목차 (Table of Contents)

• 제 I 장 서론 1
• I-1. 전자기 간섭 차폐 1
• I-2. 전자기 간섭 차폐 메커니즘 4
• I-3. 전자기 간섭 차폐 소재 8
• 제 II 장 배향성 미세 구조 설계를 통한 비산화 그래핀(NOGF)/폴리비닐리덴플루오라이드(PVDF) 복합재의 경량화 및 흡수 차폐 비율 향상 11
• II-1. 서론 12
• II-2. 실험 14
• II-2.1. 시약 14
• II-2.2. NOGF의 합성 14
• II-2.3. NOGF/PVDF 폼의 제조 15
• II-2.4. NOGF/PVDF 벌크 시편의 제조 17
• II-2.5. 분석 및 특성화 19
• II-3. 결과 및 토의 21
• II-4. 결론 37
• 제 III 장 표면 개질 자립형 맥신(MXene) 에어로겔의 이방성 충전재 네트워크 구조 설계 기반 폴리디메틸실록세인(PDMS) 복합재의 전자기 간섭 차폐 성능 차이 38
• III-1. 서론 39
• III-2. 실험 41
• III-2.1. 시약 41
• III-2.2. 맥스 상의 식각 41
• III-2.3. 물리적 충격을 통한 맥신의 박리 42
• III-2.3.1. 초음파 처리를 통한 박리 42
• III-2.3.2. 암 쉐이커를 사용한 박리 42
• III-2.4. 맥신의 수득 과정 42
• III-2.5. 자립형 맥신 에어로겔의 제조 및 열처리 43
• III-2.6. MX/PDMS 복합재의 제조 43
• III-2.7. 분석 및 특성화 46
• III-3. 결과 및 토의 48
• III-4. 결론 65