UV-absorbing Films Research Articles

UV and IR dual light triggered cellulose-based invisible actuators with high sensitivity

Actuators are widely used in bionic devices and soft robots, among which invisible actuators have some unique applications, including performing secret missions. In this paper, highly visible transparent cellulose-based UV-absorbing films were prepared by dissolving cellulose raw materials using N-methylmorpholine-N-oxide (NMMO) and using ZnO nanoparticles as UV absorbers. Furthermore, transparent actuator was fabricated by growing highly transparent and hydrophobic polytetrafluoroethylene (PTFE) film on regenerated cellulose (RC)-ZnO composite film. In addition to its sensitive response to Infrared (IR) light, the as-prepared actuator also shows a highly sensitive response to UV light, which is attributed to the strong absorption of UV light by ZnO NPs. Thanks to the drastic differences in adsorption capacity between the RC-ZnO and PTFE materials for water molecules, the asymmetrically- assembled actuator demonstrates extremely high sensitivity and excellent actuation performance, with a force density of 60.5, a maximum bending curvature of 3.0 cm−1, and a response time of below 8 s. Bionic bug, smart door and the arm of excavator made from the actuator all exhibit sensitive responses to UV and IR lights.

High UV-Absorbing Films Fabricated from Low-Cost and Lightweight Materials for Bioenvironmental Application

High UV-Absorbing Films Fabricated from Low-Cost and Lightweight Materials for Bioenvironmental Application

Control of aphids and whiteflies on Brussels sprouts by means of UV-absorbing plastic films

Use of UV-absorbing films has recently developed into a promising tool to control insect pests under greenhouse conditions. UV-absorbing films that significantly reduce transmission of UV-A and UV-B natural solar radiation can interfere with vision of herbivorous insects. The exclusion of UV from natural sunlight hampers flight initiation, dispersal, host finding and establishment, hence affects the population build-up. To study the effects of UV-absorbing films on population dynamics of Aleyrodes proletella and Brevicoryne bras-sicae, eight “walk-in” tunnels covered either with UV-absorb-ing or UV-transmitting films were constructed. In each tunnel, 49 Brussels sprouts seedlings were planted. Densities of the pest insects and their parasitation rates were determined on ten randomly chosen plants per tunnel two times per week. UV-absorbing materials significantly reduced the population densities of A. proletella and B. brassicae. Parasita-tion rates of the pests were not reduced under UV-deficient conditions. The results indicate that UV-absorbing films can be a very powerful tool to control pests in Brassica crops.

Behavioral responses of insect pests attacking leaf vegetables under ultraviolet-absorbing plastic films with different wavelengths transmitted and ultraviolet-transmitting films

The movement of five leaf vegetable insect pests, Athalia rosae ruficornis, Phyllotreta striolata, Plutella xylostella, Chromatomyia horticola and Thrips tabaci were examined with an ultraviolet (UV)-transmitting plastic film and four UV-absorbing films, which blocked wavelengths below 340 nm, 360 nm, 370 nm or 380 nm. The insects were placed in an experimental box covered with the UV-transmitting film and the UV-absorbing film; their choice behaviors were observed. The numbers of A. rosae, P. striolata and T. tabaci distributing in the area under all the UV-absorbing films tested were smaller than those under the UV-transmitting films. Movement of P. exlostella and C. horticola into areas under films blocking UV wavelengths below 360 nm,370 nm and 380 nm was suppressed compared to that with the UV-transmitting films. From these findings, we would expect the five insect pests tested to avoid light conditions that do not contain UV wavelengths of 360 nm and less.

Effect of two UV-absorbing greenhouse-covering films on growth and yield of an eggplant soilless crop

Abstract The use of UV absorbing films as greenhouse cover material is spreading out in protected cultivation. Although their effects on pest and disease management have received much attention, few studies focus on their effects on the crop. This study aims at assessing the consequences of UV absorbing film on the behaviour and production of an eggplant crop by comparing two different UV absorbing films (0 and 3% UV transmittance) to a standard polyethylene film (5% UV transmittance). Results show that the eggplants grown in the greenhouse with 0% transmission to UV light are about 21% taller and have about 17% higher leaf product (leaf length × width) than the plants grown in the greenhouse with 5% transmission to UV light. Finally, given that the production was slightly increased in quantity (20%) and quality (bigger fruits) in the greenhouse with absence of UV light compared to that with 5% transmission coefficient, it can be concluded that growing soilless eggplant under UV-absorbing material can be achieved with the same or better results as under standard covering material. Any other enhancement that the UV-absorbing film will bring (lower pest and disease impact on the crop, lower pesticide load and costs) will therefore be to the benefit of the grower.

Impact of Ultraviolet-blocking Plastic Films on Insect Vectors of Virus Diseases Infesting Crisp Lettuce

Ultraviolet (UV)-absorbing plastic films are being used as a photoselective barrier to control insect vectors and associated virus diseases in different horticultural crops. A 2-year experiment was carried out in northeastern Spain (Navarra) to evaluate the impact of a UV-blocking film (AD-IR AV) on the population density of insect pests and the spread of insect-transmitted virus diseases associated with head lettuce [Lactuca sativa (L.)]. Results showed that the UV-absorbing plastic film did not loose its ability to filter UV radiation after three lettuce crop cycles (14 months). The UV-absorbing plastic film was effective in reducing the abundance and in delaying the colonization of lettuce by aphids [Macrosiphum euphorbiae (Thomas) and Acyrthosiphum lactucae (Passerini)]. A significant increase in the percentage of marketable plants was achieved under UV-absorbing films due to a reduction in the number of plants infested by aphids and by insect-transmitted virus diseases (mainly potyviruses). Also the UV-absorbing plastic films were effective in reducing the population density of Frankliniella occidentalis (Pergande) and the spread of tomato spotted wilt virus (TSWV) as well as the population density of the lepidopteran pest, Autographa gamma (L.), a common pest of lettuce in Spain. However, no effective control of the greenhouse whitefly Trialeurodes vaporariorum (Westwood) was achieved. The results showed that UV-absorbing plastic films are a very promising tool to protect greenhouse lettuce from the main pests and insect-transmitted virus diseases occurring in northeastern Spain.

Effect of a UV-deficient environment on the biology and flight activity ofMyzus persicae and its hymenopterous parasiteAphidius matricariae

Laboratory and field experiments were conducted to study the effect of UV filtration on the population growth, distribution and flight activity of the green peach aphidMyzus persicae (Sulzer) (Homoptera: Aphididae), and on the fecundity and host-finding behavior of the parasitic waspAphidius matricariae (Haliday) (Hymenoptera: Braconidae). The work was done in the Arava Valley of Israel, in walk-in tunnels covered with polyethylene film, to compare the effects of UV-absorbing filmversus those of regular film. Following artificial aphid infestation on pepper grown under the tested films, aphid population growth and spread under the UV-absorbing films were significantly less than under the regular films. The greatest impact of UV-absorbing film on aphid behavior was observed in winter and early spring, when temperature conditions favor aphid development. Elimination of UV by UV-absorbing film did not affect the parasitic activity ofA. matricariae. Previous results had indicated that covering the greenhouse with UV-absorbing films inhibited the invasion of aphids and other insect pests into it. That effect, in combination with those described in the present paper, makes the use of UV-absorbing films an effective component of IPM that aims to reduce the application of toxic insecticides.

Preparation and Study of UV-Absorbing Multi-Layer Films

Preparation and Study of UV-Absorbing Multi-Layer Films