• English
    • Norsk
  • English 
    • English
    • Norsk
  • Administration
View Item 
  •   Home
  • Det matematisk-naturvitenskapelige fakultet
  • Fysisk institutt
  • Fysisk institutt
  • View Item
  •   Home
  • Det matematisk-naturvitenskapelige fakultet
  • Fysisk institutt
  • Fysisk institutt
  • View Item
JavaScript is disabled for your browser. Some features of this site may not work without it.

Well defined nanoparticles through controlled non-equilibrium micellization of block copolymers

Resvold, Line Trosterud
Master thesis
View/Open
master.pdf (3.476Mb)
Year
2016
Permanent link
http://urn.nb.no/URN:NBN:no-55163

Metadata
Show metadata
Appears in the following Collection
  • Fysisk institutt [2343]
Abstract
The aim of this work is to investigate if size and morphology of nanoparticles can be controlled by changing the hydrophilic ratio of the amphiphilic polymers, changing polymer concentration or simply by changing the preparation method of the particles. An amphiphilic diblock, methoxy poly(ethylene oxide)-block-polycaprolactone (PEO-PCL), with various lengths of the hydrophobic block was utilized. For accurate control of the preparation, a stopped flow apparatus (SFA) was used. The controlled co-solvent method was used for preparation of the final micelles with THF as the organic solvent. Therefore it is also natural to investigate how remaining solvent, specifically in the core, could affect the micelle, and to develop a good method for gently and effective removal of the organic solvent. Small angle X-ray scattering (SAXS) was used to measure size, aggregation number, amount of solvent in the core and radius of the micelles. The SAXS analysis also required complementary measurements of density, size, hydrophilic ratio, molecular weights, polydispersity and crystallinity. In order to obtain a complement and facilitate a thorough SAXS analysis, other measurements were performed using nuclear magnetic resonance (NMR), dynamic light scattering (DLS), densitometry, differential scanning calorimetry (DSC), and gel permeation chromatography (GPC). For the difference in polymer concentrations, 1wt% and 0.5wt%, no structural differences are observed, but by changing the block lengths of PCL from 2kDa to 4kDa an increased size and aggregation number were found. No crystallization was detected by DSC or density measurement; hence the core of the micelle in this work is amorphous. For the polymer with 2kDa PCL length, no structural effects were seen as the mixing rate was increased, hence the micelle is dynamic and in equilibrium. However, for the polymer with 4kDa PCL length, a structural change was observed for increasing mixing rate. The length of the hydrophobic block is casing the energy barrier for unimer release so high that the micelles will not gain equilibrium through unimer exchange. The micelles are in a frozen, non-equilibrium state.
 
Responsible for this website 
University of Oslo Library


Contact Us 
duo-hjelp@ub.uio.no


Privacy policy
 

 

For students / employeesSubmit master thesisAccess to restricted material

Browse

All of DUOCommunities & CollectionsBy Issue DateAuthorsTitlesThis CollectionBy Issue DateAuthorsTitles

For library staff

Login
RSS Feeds
 
Responsible for this website 
University of Oslo Library


Contact Us 
duo-hjelp@ub.uio.no


Privacy policy