Chemistry Commons^™

Electrospinning Fibers Via Complex Coacervation, Xiangxi Meng

Doctoral Dissertations

Electrospun fibers are high-surface-area materials widely used in applications ranging from batteries to wound dressings. Typically, an electrospinning precursor solution is prepared by dissolving a high-molecular-weight polymer in an organic solvent to form a sufficiently entangled solution. Our approach bypasses the requirement for entanglements and completely avoids toxic chemicals by focusing on using an aqueous complex coacervates solution. Coacervates are a dense, polymer-rich liquid phase resulting from the associative electrostatic complexation of oppositely charged macroions. We were the first to demonstrate that liquid complex coacervates could be successfully electrospun into polyelectrolyte complex (PEC) fibers. A canonical coacervate system was formed …

An Investigation Of Cross-Links On Crystallization And Degradation In A Novel, Photocross-Linkable Poly (Lactic Acid) System, Nicholas Baksh

USF Tampa Graduate Theses and Dissertations

Polymeric molecular structure consists of repeating units bonded together. Mechanicalproperties can be altered without affecting chemical makeup by altering the number of these units. Small molecules can be introduced and/or polymers can be modified to form bonds between molecular chains. Cross-linking, as this is called, also introduces mechanical variation with minimal effects on chemical composition. Lastly, polymer chains reorient themselves in response to intermolecular forces. This temperature dependent response is known as crystallization. Although chemistry is unaltered, mechanical properties can depend highly on the percent of the sample that is crystallized.

Cross-linking is known to enhance the mechanical properties of …

Effects Of Thiophene Units On Substituted Benzothiadiazole And Benzodithiophene Copolymers For Photovoltaic Applications, Ping Ding, Yingping Zou, Cheng-Che Chu, Dequan Xiao, Chain-Shu Hsu

Chemistry and Chemical Engineering Faculty Publications

Two conjugated copolymers, P1 and P2, comprising of benzodithiophene and 5, 6-dioctyloxy-benzothiadiazole (DOBT) derivatives with/without thiophene unit, were synthesized via Stille cross-coupling polymerization reaction. These copolymers are promising for the applications in BHJ solar cells due to their good solubilities， proper thermal stability and moderate hole mobility as well as low bandgap. The photovoltaic properties of the copolymers were investigated based on the blend of the different polymer/PC71BM weight ratio under AM1.5G illumination, 100 mW/cm2. The device with ITO/PEDOT:PSS/P2: PC71BM (1:2, w/w)/Ca/Al gave relatively better photovoltaic performance, with a power conversion efficiency of 1.55%.

The Synthesis, Characteristics And Performance Of Cnt Composites As Anodic Materials In Litium-Ion Battery, Quan-Feng Dong, Ming-Sen Zheng, Zhen-Cai Huang, Ming-Gang Jin, Ya-Ding Zhan, Zu-Geng Lin

Journal of Electrochemistry

As an anodic material for lithium ion battery the carbon nano-tube (CNT) and some compounds based on tin have ever been investigated intensively. The fruited progress has not been made yet, however. In this paper the composites of CNT and Sn/SnO_(2)were synthesized employing two methods and characterized by SEM and XRD. And the electrochemical performance of the composites was investigated.

New Progress In Studies Of Lithium Nickel Oxide As Positive Electrode Materials Of Lithium Ion Batteris, Han-San Liu, Yong Yang, Zhong-Ru Zhang, Zu-Geng Lin

Journal of Electrochemistry

Lithium nickel oxide as the positive electrode of lithium ion batteries has aroused more and more interests.This paper reviews the recent reserches on synthesis and element_substitution of LiNiO 2 cathode material,and summarizes the intrinsical relationship between properties and sturcture of the material.The developments of new synthesis methods and mutil_substitution of the material are expecting to be studied in the future research.