<> "The repository administrator has not yet configured an RDF license."^^ . <> . . "Field-alignment and measurement of the director in liquid\r\ncrystals and new forms of 3D printing."^^ . "3D liquid crystalline (LC) structures are complex soft materials that can exhibit stimuli-responsive\r\nmechanical deformations based on their geometry and programmed director profile. Mechanical\r\ndeformations occur when the programmed molecular orientations are disrupted, leading to collective\r\nchain-conformational changes in the polymer network. Various fabrication and alignment\r\ntechniques are available to design their 3D shape. The director profile within LC polymers determines\r\ntheir actuation profile. More complex actuation demands complete control over the 3D\r\nstructural design as well as 3D director alignment, independent of the structure’s axis. Achieving\r\nthis 3D capability with traditional techniques remains challenging. Generally, elevated temperatures\r\nand high external fields are needed or coupling of the director to the structural design,\r\nwhich restricts the 3D control. It is also challenging to determine and characterize the 3D director\r\norientation. For printing complex 3D shapes, these methods rely on sequential layer-by-layer or\r\nscanning systems which creates interfaces where the director alignment is distorted.\r\nThis thesis aims to overcome these challenges by providing effective ways to:\r\n1. Align the director in 3D within a structure,\r\n2. Characterize and visually determine the 3D director orientation in real time, and\r\n3. Enable single-shot, parallel fabrication of entire 3D complex structures with an independent\r\n3D global director.\r\nMoreover, all these techniques for alignment, characterization, and fabrication can be utilized\r\nat room temperature.\r\nThe first project focuses on spatially patterning complex 3D director orientations voxel by\r\nvoxel using weak magnetic fields. We prepare an LC gel ink formulation containing the nonreactive\r\nmesogens E7 and 5CB, which facilitate magnetic alignment control at room temperature.\r\nThe director can be oriented in any desired direction by rotating the external magnetic fields.\r\nA Wollaston prism with a spatially varying 3D optic axis is fabricated to demonstrate the arbitrary\r\n3D director alignment control and fabrication of advanced 3D LC optical elements at room temperature.\r\nThe second project introduces an optical method for characterizing 3D director orientation\r\nusing a wedge cell technique, which enables the real-time visual determination of the 3D director\r\norientation. It is based on the birefringence influenced by the out-of-plane director alignment. The\r\nin-plane and out-of-plane director orientations are measured and calculated based on polarization\r\nstates and the angular separation of the beam splitting. This method provides a fast and reliable\r\nprotocol for precisely determining the 3D director orientation.\r\nThe third project aims to fabricate entire 3D structures in a single exposure at room temperature\r\nwhile maintaining the 3D director alignment independent of the structure’s geometry.\r\nTo achieve this, optical holographic lithography is shown to generate 3D light intensity patterns\r\nfor the direct polymerization of 3D shapes in a single exposure. The single shot holographic\r\nfabrication of 4D liquid crystals actuators is demonstrated."^^ . "2025" . . . . . . . "Lovish"^^ . "Gulati"^^ . "Lovish Gulati"^^ . . . . . . "Field-alignment and measurement of the director in liquid\r\ncrystals and new forms of 3D printing. (PDF)"^^ . . . "PhD_thesis_Lovish_Gulati_30.06.2025.pdf"^^ . . . "Field-alignment and measurement of the director in liquid\r\ncrystals and new forms of 3D printing. (Other)"^^ . . . . . . "lightbox.jpg"^^ . . . "Field-alignment and measurement of the director in liquid\r\ncrystals and new forms of 3D printing. (Other)"^^ . . . . . . "preview.jpg"^^ . . . "Field-alignment and measurement of the director in liquid\r\ncrystals and new forms of 3D printing. (Other)"^^ . . . . . . "medium.jpg"^^ . . . "Field-alignment and measurement of the director in liquid\r\ncrystals and new forms of 3D printing. (Other)"^^ . . . . . . "small.jpg"^^ . . . "Field-alignment and measurement of the director in liquid\r\ncrystals and new forms of 3D printing. (Other)"^^ . . . . . . "indexcodes.txt"^^ . . "HTML Summary of #37083 \n\nField-alignment and measurement of the director in liquid \ncrystals and new forms of 3D printing.\n\n" . "text/html" . .