A kind of water-soluble polyfluorene nanoparticles prepared by inclusion complexation of β-cyclodextrin

First. The ATRP initiator monosubstituted β-CD-Br was successfully prepared, which was confirmed by ¹H-NMR and MALDI-TOF. And then the water-soluble polymer (β-CD-PDMAEMA) modified with β-CD at the one end was synthesised by ATRP polymerization. The β-CD-PDMAEMA and PF-ADA can form water-soluble nanoparticle (PF-NP) via the host-guest inclusion complexation between β-CD and adamantane (ADA) as driving force. Dynamic light scattering (DLS) was employed to measure the effect of weight ratio of β-CD-PDMAEMA/PF-ADA on R_h and PDI of PF-NP. The DLS results show that the weight ratio of β-CD-PDMAEMA/PF-ADA with 4: 1 could form smaller nanoparticle, the R_h is 119 nm. As well as four diffent self-assembly methods impact on character of nanoparticles were also focused, while fixing the weight ratio of β-CD-PDMAEMA/PF-ADA at 4: 1. When 4 mL water was slowly injected into 1 mL THF solution of β-CD-PDMAEMA and PF-ADA under ultrasonication, the R_h of nanoparticle is equal to 81 nm. Transmission electron microscopy (TEM) and atomic force microscopy (AFM) were used to exam the morphology of nanoparticles. The results from TEM and AFM show that the nanoparticles are spherical with diameter of 100 nm, which is smaller than the results observed from DLS measuements. It is well-known that PDMAEMA chains exhibit a coil-to-globule transition above their lower critical solution temperature (LCST) in water solution. At last, the R_h of nanoparticles decreases with temperature increase. All these results show that the nanoparticles have the PF polymer as the core, with diameter of 100 nm and the PDMAEMA polymer as the shell with thick ness of 30 nm.