Interface Directed Self-Assembly of Liquid Crystal-Nanoparticle Hybrid Materials Yifan Ning

Format:

Book

Thesis/Dissertation

Author/Creator:

Ning, Yifan, author.

Contributor:

University of Pennsylvania. Chemistry., degree granting institution.

Language:

English

Subjects (All):

Nanoscience.

Chemistry.

Materials science.

0794.

0565.

0485.

Local Subjects:

Nanoscience.

Chemistry.

Materials science.

0794.

0565.

0485.

Physical Description:

1 electronic resource (429 pages)

Contained In:

Dissertations Abstracts International 86-12B

Place of Publication:

Ann Arbor : ProQuest Dissertations and Theses, 2025

Language Note:

English

Summary:

The self-assembly of nanoparticles (NPs) has broad applications. This process is controlled by the NP cores and the molecular interactions at the interfaces between ligands and their environments, which impart dynamics to the assembled superlattices (SLs) with temperature changes. Designing and understanding temperature-sensitive interfaces to precisely manipulate NPs is critical in the fabrication of high-quality SLs with desired structures and properties. Liquid crystals (LCs) are promising candidates as thermo-responsive materials. The LC-NP hybrid materials, including NPs with liquid crystalline ligands and NP dopants in LC matrices, have active yet complex interfaces, offering opportunities and challenges to manipulate these nanomaterials' dynamics, structures, and properties.This thesis starts with dried NP aggregates with liquid crystalline ligands and the dynamics of ligand-ligand interfaces. These ligands are also referred to as (pro)mesogenic ligands. Traditional NPs lack mobility in the dried state due to the interdigitation of ligand tails. Tailored dendritic promesogenic ligands with a thermally triggerable lubricating property induce dried NP aggregates to transform from a random state to ordered SLs with preferred orientations by heating or laser illumination. Simulations reveal the promesogenic ligands with flexible chains do not interdigitate, increasing the mobility of NPs. Next, NP dopants in LC matrices and the ligand-environment interfaces are investigated. In an anisotropic LC environment, an ellipsoidal ligand shell on a spherical NP is induced, aligns with the LC orientation, and can be manipulated indirectly with a magnetic field. A novel methodology for growing SLs reversibly from LCs is developed. LCs serve as temperature-responsive solvents to disperse NPs in the isotropic phase and expel NPs in the LC phases. Experiments and simulations demonstrate that the expelled NPs co-crystallize with LC molecules into solid solutions, where LC molecules occupy the voids and diffuse in/out of the SLs with temperature changes. Manipulating the interfaces between promesogenic ligands and LCs can tune the SL growth mode and achieve reversible SL phase transformations. Moreover, a fibrillar network of nanoplate self-assembly can gelate fluidic LCs, highlighting the synergistic and mutual interaction between NPs and LCs

Notes:

Source: Dissertations Abstracts International, Volume: 86-12, Section: B.

Advisors: Murray, Christopher B. Committee members: Fakhraai, Zahra; Walsh, Patrick J.; Osuji, Chinedum O.

Ph.D. University of Pennsylvania 2025

Local Notes:

School code: 0175

ISBN:

9798280760745

Access Restriction:

Restricted for use by site license