Chemical defects in the highly fluorescent conjugated polymer dots.
We present strong evidence for the oxidation of conjugated polymers in the formation of conjugated polymer dots (CPdots) using Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy. Although recent studies show that folding of the polymer chain into a compact 3D structure is involved in the formation of these nanoparticles, the process by which these intrinsically hydrophobic nanoscale particles circumvent aggregation in water is still not well understood. Zeta potential results show that these dots have a negatively charged surface at neutral pH, with a zeta potential and surface charge density of approximately -40 mV and (1.39 - 1.70) × 10(-2) C/m(2), respectively. In addition, quantitative elemental analysis of CPdots indicates that oxygen composes 7-13% of these nanoparticles. The overall results support the presence of chemical defects in forming a hydrophilic surface of CPdots. As a consequence, the charged surface contributes to inhibiting the aggregation of CPdots in water, leading to colloidal stability.
Department of Chemistry, University of Adelaide, Adelaide, South Australia 5005, Australia.
Scott N
SN
Clafton
David A
DA
Beattie
Agnieszka
A
Mierczynska-Vasilev
Robert G
RG
Acres
Alan C
AC
Morgan
Tak W
TW
Kee
D003102:Colloids / Q000737:chemistry; D005456:Fluorescent Dyes / Q000494:pharmacology; D057927:Hydrophobic and Hydrophilic Interactions; D018625:Microscopy, Atomic Force / Q000379:methods; D053758:Nanoparticles / Q000737:chemistry; D036103:Nanotechnology / Q000379:methods; D010100:Oxygen / Q000737:chemistry; D010316:Particle Size; D011108:Polymers / Q000737:chemistry*; D013050:Spectrometry, Fluorescence / Q000379:methods; D013052:Spectrometry, X-Ray Emission / Q000379:methods*; D013056:Spectrophotometry, Ultraviolet / Q000379:methods; D017550:Spectroscopy, Fourier Transform Infrared / Q000379:methods
D003102:Colloids; D005456:Fluorescent Dyes; D011108:Polymers; D010100:Oxygen