Reversible photochromic properties of TiO2-polymer nanocomposites.

J Nanosci Nanotechnol

Departement of Materials, Eidgenössische Technische Hochschule (ETH) Zürich, ETH Hönggerberg HCI H509, CH-8093 Zürich, Switzerland.

Published: February 2006

Composite films of nanosized TiO2 particles, which contained rutile as the only detected crystal modification, and poly(vinyl alcohol), poly(vinyl pyrrolidone) or poly(4-vinylpyridine) were prepared from aqueous dispersions. During exposure to UV irradiation the nanocomposites comprising poly(vinyl alcohol) or poly(vinyl pyrrolidone) turned blue as a consequence of a partial reduction of TiIV to TiIII. The color intensity increased with increasing TiO2 content and irradiation time. This color did not fade after removal of the UV source in spite of the sensitivity of TiIII to atmospheric oxygen. By contrast, exposure to water caused the nanocomposites to adopt their original colorless appearance. These colorization-decolorization cycles could be repeated more than 10 times without apparent loss of intensity. Due to the small size of the TiO2 nanoparticles (ca. 3 nm), patterned blue structures of high resolution could be created in the polymeric materials, for instance with simple masking methods.

Download full-text PDF

Source
http://dx.doi.org/10.1166/jnn.2006.923DOI Listing

Publication Analysis

Top Keywords

polyvinyl alcohol
8
alcohol polyvinyl
8
polyvinyl pyrrolidone
8
reversible photochromic
4
photochromic properties
4
properties tio2-polymer
4
tio2-polymer nanocomposites
4
nanocomposites composite
4
composite films
4
films nanosized
4

Similar Publications

An electro- and optically favorable quaternary nanocomposite film was produced by solution-casting nickel oxide nanoparticles (NiO NPs) into polyvinyl alcohol (PVA), polyvinyl pyrrolidone (PVP), and poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT/PSS). Based on transmission electron microscopy (TEM) and X-ray diffraction (XRD) observations, the synthesized NiO NPs have a cubic phase and a diameter between 10 and 45 nm. The complexity and interactions observed through XRD patterns, UV-visible spectra, and FTIR measurements suggest that the NPs are not just dispersed within the polymer matrix, but are interacting with it, leading to enhanced dielectric properties and AC electrical conductivity.

View Article and Find Full Text PDF

Application of lanthanum-modified silk fibroin/polyvinyl alcohol film for highly selective defluoridation in brick tea infusion.

Int J Biol Macromol

January 2025

State Key Laboratory of Tea Plant Biology and Utilization, Joint Research Center for Food Nutrition and Health of IHM and Anhui Provincial Key Laboratory of Food Safety Monitoring and Quality Control, Anhui Agricultural University, Hefei 230036, PR China; College of Food and Nutrition, Anhui Agricultural University, Hefei 230036, PR China. Electronic address:

To mitigate the risk associated with water-soluble fluoride in tea and to have less influence on the contents of tea infusion, a highly selective lanthanum modified silk fibroin (SF) and polyvinyl alcohol (PVA) composite film (SF/PVA-La) was prepared to remove fluoride from brick tea infusion. Notably, SF/PVA-La could remove about 48 % of the fluoride from in brick tea infusion within 30 min. Importantly, the reduction in total tea polyphenols in brick tea did not exceed 10 %, and the reduction in caffeine was only 0.

View Article and Find Full Text PDF

Smart packaging, also known as intelligent packaging, is responsive to external stimuli, moisture, light, oxygen, heat, pH, and bacterial growth. In this study, polyvinyl alcohol/nanochitosan/phycocyanin nanocomposite (PVA/NCH/PC-NC) for fish fillets of Oncorhynchus mykiss rainbow trout coating was prepared. Five treatments were prepared over a period of 14 days (0, 1, 7 and 14 days) under treatments of T: fish coated with PVA/NCH-NC without PC; T, T T and T fish coated with PVA/NCH/PC-NC (0.

View Article and Find Full Text PDF

Compounds containing the piperidine group are highly attractive as building blocks for designing new drugs. Functionalized piperidines are of significant interest due to their prevalence in the pharmaceutical field. Herein, 3-oxo-3-(piperidin-1-yl) propanenitrile has been synthesized, and piperidine-based sodium alginate/poly(vinyl alcohol) films have been prepared.

View Article and Find Full Text PDF

Dual-Modality Flow Phantom for Ultrasound and Optical Flow Measurements.

Phys Med Biol

January 2025

Schlegel Research Institute for Aging, University of Waterloo, 250 Laurelwood Drive, Waterloo, Ontario, N2L 3G1, CANADA.

As ultrasound-compatible flow phantoms are devised for performance testing and calibration, there is a practical need to obtain independent flow measurements for validation using a gold-standard technique such as particle image velocimetry (PIV). In this paper, we present the design of a new dual-modality flow phantom that allows ultrasound and PIV measurements to be simultaneously performed. Our phantom's tissue mimicking material is based on a novel hydrogel formula that uses propylene glycol to lower the freezing temperature of an ultrasound-compatible poly(vinyl) alcohol cryogel and, in turn, maintain the solution's optical transparency after thermocycling.

View Article and Find Full Text PDF

Want AI Summaries of new PubMed Abstracts delivered to your In-box?

Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!