Synthesis Of Polymer Nanomaterials And Their Applications As Near-infrared Photoabsorbing Materials

Near-infrared-absorbing materials,which can effectively absorb the near-infrared light(700nm-2.5?m)and convert the near-infrared light which have been widely applied in the fields of energy-saving,environmental and biomedical materials,etc.At present,two types of NIR absorbing materials have been mainly developed.One is inorganic materials,such as noble metal nanoparticles(Au,Ag,Pd),semiconductors(Cu-based,W-based),metal-oxide semiconductor nanomaterials(ITO,ATO,and AZO)and carbon materials.These materials can absorb part of NIR light,however,these NIR absorbing inorganic materials still have some shortcoming.Metal nanomaterials are expensive,unable to be degraded,poor metabolizers.And carbon materials require surface modification,so the synthesis process is too complicated.The second one is organic materials,such as indocyanine green(ICG),polyaniline,melanin,polypyrrole(PPy),etc.They exhibit excellent biocompatibility,optical stability and excellent NIR shielding properties(range 1000-2700 nm).Polypyrrole as an organic conjugated polymer has excellent NIR absorption properties and biocompatibility,which has significant potential applications in energy environmental protection and bio-treatment.In this paper,we have designed a synthesis for PPy nanoparticles by a modified one-step aqueous dispersion polymerization method and explored PPy applications in NIR shielding films with smart composite microgels.Main works have been listed as follows:Part 1: PANI sample was prepared by a modified interfacial polymerization method [14],and its morphology and size were studied by scanning electron microscopy(SEM)and transmission electron microscopy(TEM)images.Obviously,PANI sample consists of spherical nanoparticles with sizes of 100~250 nm.The sample was further analyzed by FT-TR spectrum,and one can confirm that there are both PANI and SDBS in the sample.As a result of the presence of SDBS,PANI nanospheres are hydrophobic and can be easily dispersed in chloroform.The sample was further studied by UV-vis-NIR spectroscopy,There is a peak located at NIR region from 700 to 850 nm with a maximum absorbance at 756 nm(~2.1),indicating high NIR-absorbing ability.Furthermore,the photoabsorption in visible region(460~600 nm)is very low with the lowest absorbance at 502 nm(~0.18),suggesting high visible-transmittance.These facts reveal that PANI nanospheres can selectively absorb NIR light while transmit visible light.Part 2: we have developed full-polymer NIR shielding films by using polyaniline(PANI)nanospheres(100~250 nm)as the NIR absorbent and polyacrylic acid resin(PAA)as the matrix.The PANI-PAA films are transparent in the visible region(480~650 nm)but can shield NIR(700~900 nm)light selectively,and their visible-transmittance/NIR-shielding properties can be controlled by changing PANI content.For a typical PANI-PAA film(0.20-mm-thick,0.75 wt% PANI),the shielding efficiency of 808-nm laser is about 80.5%.Therefore,these PANI-PAA films with selective NIR shielding properties have great potential in the field of NIR protection and/or energy-saving coatings.Part 3: Near-infrared(NIR)laser-induced photothermal ablation therapy(PAT)has been demonstrated to have great potential to cure tumors,and a prerequisite is to obtain biocompatible and efficient photothermal agents.We synthesized P(NIPAM-co-NVP)composite temperaturesensitive microgels.Above all,P(NIPAM-co-NVP)microgels(a mean size ~ 500 nm)have been synthesized by precipitation polymerization.Based on the foundation of the microgels,PEDOT nanoparticles with diameter of ~ 50 nm are synthesized by a simple chemical oxidation polymerization route and the nanoparticles uniform growth/adsorb in P(NIPAM-co-NVP)microgels surface.The as-prepared microgels exhibit excellent photothermal performance under 808 nm laser.The temperature increased from room temperature from 30°C to 67.08°C with 50 ?g mL-1 PEDOT composite microgels for 5 minutes under the irradiation.The temperature elevation(37.08°C)is remarkably higher compared with that(1.07 °C)from deionized water as solution under the other identical condition.Furthermore,the smart composite microgels also exhibit strong absorption in NIR region and volume phase inversion temperature(VPIT)at about 40°C.Therefore,PEDOTP(NIPAM-co-NVP)full-polymer smart composite microgels have great potential as a novel NIR absorption materials for the design and development of photothermal treatment.