ABSTRACT
A durable superhydrophobic, self-cleaning cotton fabric prepared with UV curing was prepared by a simple method and used for oil/water separation. Firstly, sulfhydryl silica nanoparticles on the fabric surface were prepared by the Stöber reaction (SiO2-SH@cotton). Then, the side chain hydroxyl terminated PDMS was reacted with isocyanate to form an isocyanate terminated prepolymer. The prepolymer terminated by HEMA (vinyl-terminated PDMS (PIH)) was sprayed on the fabric surface, and then the superhydrophobic coating (SiO2-S-PIH@cotton) was formed using UV curing. A series of characterization methods were used to demonstrate the properties of the modified cotton fabric. When the weight gain after PIH spraying was 1.8 wt%, the fabric reaches an optimal state (water contact angle (WCA) of 153° and a sliding angle of 7°). When used in an oil-water separation test, the highest separation efficiency reached 99.1%. In particular, the as-prepared fabric has excellent wear resistance. Compared with that before spraying, the superhydrophobicity of the as-prepared fabric has no obvious decrease after 300 cycles under 200 g of weight or after 100 cycles under 500 g of circular friction. This indicated that surface sprayed polymers have two functions: providing low surface tension and protecting the rough surface formed by silica particles. This process was time-saving, energy-saving, protected the environment, had a low material cost and a strong performance stability. It is hoped that this fabric can be used in the large-scale industrialization of oil-water separation.
ABSTRACT
OBJECTIVE: To observe blood pressure change with age in salt-sensitive teenagers whose salt sensitivity were determined by repeated testing. METHODS: Salt sensitivity was determined through intravenous infusion of normal saline combined with volume-depletion by oral diuretic furosemide in 55 teenagers. After five years, salt sensitivity was re-examined and subject blood pressure was followed up. Blood pressure changes in salt-sensitive teenagers were compared to that of non-salt sensitive teenagers over five years. RESULTS: After 5 years, the repetition rate of salt sensitivity determined by intravenous saline loading is 92.7%. In teenagers with salt sensitivity on the baseline, both the systolic blood pressure increments and increment rates were much higher than non-salt sensitive teenagers (12.7 +/- 12.1 mmHg vs. 2.8 +/- 5.2 mmHg, P < 0.01; 12.2% +/- 12.0% vs. 2.5% +/- 4.4%, P < 0.001, respectively). There was a similar trend for diastolic blood pressure (8.4 +/- 6.4 mmHg vs. 3.7 +/- 6.4 mmHg, P = 0.052; 13.2% +/- 10.6% vs. 6.8% +/- 10.1%, P = 0.053, respectively). CONCLUSIONS: Salt sensitivity determined by intravenous saline loading showed good reproducibility. Blood pressure increments with age were much higher in salt-sensitive teenagers than non-salt sensitive teenagers, especially in terms of systolic blood pressure.
