Off-campus UMass Amherst users: To download campus access dissertations, please use the following link to log into our proxy server with your UMass Amherst user name and password.
Non-UMass Amherst users: Please talk to your librarian about requesting this dissertation through interlibrary loan.
Dissertations that have an embargo placed on them will not be available to anyone until the embargo expires.
Author ORCID Identifier
https://orcid.org/0000-0002-2715-5198
AccessType
Campus-Only Access for One (1) Year
Document Type
dissertation
Degree Name
Doctor of Philosophy (PhD)
Degree Program
Polymer Science and Engineering
Year Degree Awarded
2021
Month Degree Awarded
May
First Advisor
Kenneth R. Carter
Subject Categories
Polymer and Organic Materials | Polymer Science
Abstract
Governments and scientists all over the planet have recognized the importance of pursuing and achieving sustainability. As the human population grows and technologies advance, the planet’s limited resources become less and less able to support our taxing demands. In 2015, the United Nations set forth 17 Sustainable Development Global Goals. Goal 12 “Responsible Production and Consumption” can be addressed quite readily by the integration of sustainable materials into advanced technologies; however, such materials have yet to be developed. Cellulose nanocrystals (CNCs) – an abundant, well-known sustainable nanomaterial hydrolyzed from bulk cellulose with high surface functionality and high strength properties – have immense potential as building blocks for sustainable composites, but very few synthetic and analytical strategies used to produce and learn about these composites are currently understood. This dissertation work describes synthetic methods and analytical techniques used to develop and characterize CNC composite materials. CNCs were exchanged from water into anhydrous organic media via extensive viii solvent exchange procedures, thereby enabling water-sensitive surface modifications using a variety of organic small molecule and polymer syntheses. Surface bound materials imparted an array of properties non-native to cellulosic materials. These composite materials combined the sustainable substrate properties of CNCs with properties desirable in advance applications. Through a series of investigations, families of novel CNC derivatives were designed and produced including a semiconducting CNC/polyfluorene emitter material and a t-Boc modified CNC hydrophobic coating material. Semiconducting grafted polyfluorene-CNC composites sported grafted polymer molecular weights above the effective conjugation length of polyfluorene and, when employed as an OLED emitter layer, proved to have comparable properties with homopolymer polyfluorene standards. Small molecule t-Boc modified CNC composites demonstrated hydrophobic behaviors that, when complemented with a photoacid generator, could be cast into films and coatings and subsequently photopatterned to yield selectively designed water guiding or confining channels. Furthermore, numerous synthetic and processing parameters were determined to give precise control of properties, thus giving a single CNC derivative immense versatility and applicability. The results of this work unveil how novel CNC composites can be designed for sustainable advanced technologies.
DOI
https://doi.org/10.7275/22181256.0
Recommended Citation
Chang, Allen C., "Surface Modification of Cellulose Nanocrystals: Imparting Non-native Properties on Sustainable Substrates" (2021). Doctoral Dissertations. 2169.
https://doi.org/10.7275/22181256.0
https://scholarworks.umass.edu/dissertations_2/2169