ساز و كار تشكيل و پايداري كلوئيد نانو ذرات نقره با استناد به تئوري هاي مرتبط

Mechanism of formation and stability of silver nanoparticle colloids and their characteristics according to related theories

ذرات با اندازه بين 100-1 نانومتر نانوذره ناميده مي شوند كه نسبت سطح به حجم آنها بيشتر از حالت توده است. اصطلاح كلوئيد در صورتي اعمال مي گردد كه ذرات سطح بزرگ تر و حجم كوچك تري داشته باشند لذا نانوذرات قادر به توليد كلوئيد هستند. به علت استفاده گسترده از نانوذرات نقره ممكن است در هنگام ساخت، استفاده و يا بعد از فرسوده شدن به محيط زيست آزاد شوند و بر روي اكوسيستم و ميكروارگانيسم ها اثر مضري بگذارند. سميت نانوذرات نقره در هر اكوسيستم تاحد زيادي به پايداري كلوئيد نقره وابسته است. عواملي كه مانع كلوخه اي شدن نانوذرات مي گردند پايدار كننده محسوب مي شوند. پايداري كلوئيدها تابع عوامل بسياري شامل نوع عامل پوشاننده و شرايط محيطي است. سه نوع مكانيسم پايداري نانوذرات وجود دارد كه در اين مطالعه به بررسي مكانيسم تشكيل و پايداري نانوذرات مي پردازيم.

Particles in the size between 1-100 nm are called nanoparticles whose surface-to-volume ratio is greater than the bulk. The term of colloid is applied if the particles have larger surface and smaller volume, so nanoparticles can produce colloid. The study of colloid phenomena is known as colloid science, leading to technological advances including ceramic processing, coating, pharmaceuticals, and etc. Due to antibacterial properties, silver nanoparticles are used in medical equipment and textiles fabrics, as well as in cosmetics, hygiene and plastics. Due to its widespread use, silver nanoparticles may be released to the environment when they are being built and used by consumers or after wearing out. The main concern for the release of silver nanoparticles in environment is due to their effect on the ecosystem and microorganisms. The bioavailability and toxicity of silver nanoparticles in each ecosystem is highly dependent on the stability of silver colloid. Factors that prevent the agglomeration of nanoparticles are considered to be stabilizing. The stability of colloids depends on many factors, including the type of covering agent, environmental conditions including pH and ionic strength. There are three types of nanosilver stability mechanisms that include electrostatic repulsion, spatial repulsion, and electrostatic and spatial repulsion simultaneously. Considering the importance of stabilizers in the synthesis of nanoparticles, in this study the stability of nanoparticles and the stability mechanisms of nanoparticles were investigated.