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Architected Liquid Crystal Elastomers With Spatially Programmed Alignment, Shape Morphing, and Mechanics
Architected Liquid Crystal Elastomers With Spatially Programmed Alignment, Shape Morphing, and Mechanics
상세정보
- 자료유형
- 학위논문 서양
- 최종처리일시
- 20260202103527
- ISBN
- 9798280710719
- DDC
- 620
- 저자명
- Telles, Rodrigo.
- 서명/저자
- Architected Liquid Crystal Elastomers With Spatially Programmed Alignment, Shape Morphing, and Mechanics
- 발행사항
- [Sl] : Harvard University, 2025
- 발행사항
- Ann Arbor : ProQuest Dissertations & Theses, 2025
- 형태사항
- 148 p
- 주기사항
- Source: Dissertations Abstracts International, Volume: 86-12, Section: B.
- 주기사항
- Advisor: Lewis, Jennifer A.
- 학위논문주기
- Thesis (Ph.D.)--Harvard University, 2025.
- 초록/해제
- 요약Liquid crystal elastomers (LCEs) are responsive soft materials that undergo reversible shape morphing when cycled above their nematic-to-isotropic transition temperature. This property, coupled with their programmable alignment and mechanics, makes LCEs ideal for advanced applications in adaptive structures, energy absorption, and artificial muscles. However, fabricating monolithic LCEs with spatially varying director alignment in arbitrary architected structures remains a significant challenge. To address this, my Ph.D. thesis focuses on developing a universal framework to correlate printing conditions with director alignment, laying the groundwork for fabricating architected LCE lattices with spatially programmed alignment, shape morphing, and mechanics.During extrusion-based 3D printing, LCE inks experience coupled shear and extensional flows, that enable spatial control of nematic director alignment along prescribed print paths. Combining experiments and computational modeling, we investigated the effects of ink composition, nozzle geometry, and printing parameters on flow-induced alignment. Rheological measurements revealed that the Weissenberg number (Wi) strongly predicts alignment, with uniform alignment achieved at Wi 1. COMSOL simulations and in-operando X-ray measurements confirm that hyperbolic nozzles produced printed LCE architectures with improved alignment compared to tapered nozzles, resulting in enhanced stiffness and actuation strain. By varying Wi during printing, LCE architectures with uniform composition yet locally encoded degree of alignment, and hence shape-morphing transitions were realized.Next, we fabricated architected LCE lattices with a high degree of flow-induced alignment via direct ink writing and systematically characterized their shape morphing, stiffness, and energy absorption across strain rates spanning six orders of magnitude. Compared to non-mesogenic elastomeric (silicone) counterparts, LCE lattices exhibit superior energy absorption, with energy absorption ratios up to 18-fold higher at the highest strain rates. A finite element model capturing their shape-morphing response shows excellent agreement with experimental data. In summary, this work demonstrates the potential of architected LCEs as programmable soft materials for myriad applications that require stimuli-responsive, tunable properties.
- 일반주제명
- Engineering
- 일반주제명
- Materials science
- 일반주제명
- Energy
- 일반주제명
- Mechanics
- 키워드
- Active lattices
- 키워드
- Shape morphing
- 키워드
- X-ray scattering
- 기타저자
- Harvard University Engineering and Applied Sciences - Engineering Sciences
- 기본자료저록
- Dissertations Abstracts International. 86-12B.
- 전자적 위치 및 접속
- 로그인 후 원문을 볼 수 있습니다.
MARC
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■00520260202103527
■006m o d
■007cr#unu||||||||
■020 ▼a9798280710719
■035 ▼a(MiAaPQ)AAI32039468
■040 ▼aMiAaPQ▼cMiAaPQ
■0820 ▼a620
■1001 ▼aTelles, Rodrigo.▼0(orcid)0000-0001-5785-6289
■24510▼aArchitected Liquid Crystal Elastomers With Spatially Programmed Alignment, Shape Morphing, and Mechanics
■260 ▼a[Sl]▼bHarvard University▼c2025
■260 1▼aAnn Arbor▼bProQuest Dissertations & Theses▼c2025
■300 ▼a148 p
■500 ▼aSource: Dissertations Abstracts International, Volume: 86-12, Section: B.
■500 ▼aAdvisor: Lewis, Jennifer A.
■5021 ▼aThesis (Ph.D.)--Harvard University, 2025.
■520 ▼aLiquid crystal elastomers (LCEs) are responsive soft materials that undergo reversible shape morphing when cycled above their nematic-to-isotropic transition temperature. This property, coupled with their programmable alignment and mechanics, makes LCEs ideal for advanced applications in adaptive structures, energy absorption, and artificial muscles. However, fabricating monolithic LCEs with spatially varying director alignment in arbitrary architected structures remains a significant challenge. To address this, my Ph.D. thesis focuses on developing a universal framework to correlate printing conditions with director alignment, laying the groundwork for fabricating architected LCE lattices with spatially programmed alignment, shape morphing, and mechanics.During extrusion-based 3D printing, LCE inks experience coupled shear and extensional flows, that enable spatial control of nematic director alignment along prescribed print paths. Combining experiments and computational modeling, we investigated the effects of ink composition, nozzle geometry, and printing parameters on flow-induced alignment. Rheological measurements revealed that the Weissenberg number (Wi) strongly predicts alignment, with uniform alignment achieved at Wi 1. COMSOL simulations and in-operando X-ray measurements confirm that hyperbolic nozzles produced printed LCE architectures with improved alignment compared to tapered nozzles, resulting in enhanced stiffness and actuation strain. By varying Wi during printing, LCE architectures with uniform composition yet locally encoded degree of alignment, and hence shape-morphing transitions were realized.Next, we fabricated architected LCE lattices with a high degree of flow-induced alignment via direct ink writing and systematically characterized their shape morphing, stiffness, and energy absorption across strain rates spanning six orders of magnitude. Compared to non-mesogenic elastomeric (silicone) counterparts, LCE lattices exhibit superior energy absorption, with energy absorption ratios up to 18-fold higher at the highest strain rates. A finite element model capturing their shape-morphing response shows excellent agreement with experimental data. In summary, this work demonstrates the potential of architected LCEs as programmable soft materials for myriad applications that require stimuli-responsive, tunable properties.
■590 ▼aSchool code: 0084.
■650 4▼aEngineering
■650 4▼aMaterials science
■650 4▼aEnergy
■650 4▼aMechanics
■653 ▼aActive lattices
■653 ▼aDirect ink writing
■653 ▼aEnergy absorption
■653 ▼aLiquid crystal elastomers
■653 ▼aShape morphing
■653 ▼aX-ray scattering
■690 ▼a0794
■690 ▼a0537
■690 ▼a0346
■690 ▼a0791
■71020▼aHarvard University▼bEngineering and Applied Sciences - Engineering Sciences.
■7730 ▼tDissertations Abstracts International▼g86-12B.
■790 ▼a0084
■791 ▼aPh.D.
■792 ▼a2025
■793 ▼aEnglish
■85640▼uhttp://www.riss.kr/pdu/ddodLink.do?id=T17357547▼nKERIS▼z이 자료의 원문은 한국교육학술정보원에서 제공합니다.
