| dc.contributor |
Tatyana I. Smirnova, Committee Member |
|
| dc.contributor |
Lin He, Committee Member |
|
| dc.contributor |
Alex Deiters, Committee Member |
|
| dc.contributor |
Bruce M. Novak, Committee Chair |
|
| dc.creator |
Li, Haibo |
|
| dc.date |
2010-04-02T19:12:06Z |
|
| dc.date |
2010-04-02T19:12:06Z |
|
| dc.date |
2006-08-04 |
|
| dc.date.accessioned |
2023-02-28T17:07:08Z |
|
| dc.date.available |
2023-02-28T17:07:08Z |
|
| dc.identifier |
etd-07082006-222011 |
|
| dc.identifier |
http://www.lib.ncsu.edu/resolver/1840.16/5345 |
|
| dc.identifier.uri |
http://localhost:8080/xmlui/handle/CUHPOERS/265500 |
|
| dc.description |
As a helical polymer, polycarbodiimides have been investigated for a period of time. But few water soluble polycarbodiimides had been synthesized and characterized. Since solubility of polycarbodiimides can be controlled by their side arms, achiral or chiral carbodiimides bearing hydrophilic tertiary amino group have been prepared. Single-handed sense hydrophilic polycarbodiimides were prepared from chiral monomers by achiral metal catalyst or from achiral monomers by chiral catalyst to give polycarbodiimides with predominately helical sense. The water solubility of these polycarbodiimides bearing tertiary amino groups is improved when they are methylated by methyl camphorsulfornic acid ester. Configurational and conformational predominately helical polycarbodiimides behave with different way when they are heated. For the former case, the polymers rearrange to their Thermodynamic Control Conformation (TCC) from Kinetic Control Conformation (KCC); for the later one, the polymer became racemic when annealed. The activation energies for the conformational change can be determined through Arrhenius plot analysis. Compared to the neutral polycarbodiimides bearing tertiary amino groups, the corresponding ionic polymers have higher activation energies. Helical induction of the water-soluble polycarbodiimides also has been investigated. CD spectrum was run for both the neutral and ionic polycarbodiimides and peptide mimics were found.
In addition to the hydrophilic monomers, chiral or achiral hydrophobic carbodiimides were also synthesized and polymerized. Through living polymerizations, the amphiphilic polycarbodiimides were prepared from metal catalysts. Crew-cut nanoparticles have been prepared through a phase inversion method. Different conditions have been tried to achieve nano particles with different morphologies and sizes. In the nano particle preparation, water amount, acid amount and molecular weight play important roles in preparation of nano particles. TEM was used to characterize the nano particles. Amphiphilic polycarbodiimides with optical active hydrophobic blocks were synthesized and applied in the preparation of a nano-superhelix. |
|
| dc.rights |
I hereby certify that, if appropriate, I have obtained and attached hereto a written permission statement from the owner(s) of each third party copyrighted matter to be included in my thesis, dissertation, or project report, allowing distribution as specified below. I certify that the version I submitted is the same as that approved by my advisory committee. I hereby grant to NC State University or its agents the non-exclusive license to archive and make accessible, under the conditions specified below, my thesis, dissertation, or project report in whole or in part in all forms of media, now or hereafter known. I retain all other ownership rights to the copyright of the thesis, dissertation or project report. I also retain the right to use in future works (such as articles or books) all or part of this thesis, dissertation, or project report. |
|
| dc.subject |
nano particles |
|
| dc.subject |
helical polymer |
|
| dc.subject |
water soluble polymer |
|
| dc.title |
Investigation of Helicity of Water Soluble Polycarbodiimides and Preparation of Nano Particles with Amphiphilic Polycarbodiimides. |
|