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首页> 外文期刊>The Journal of Chemical Physics >Size distributions of metal nanoparticles in polyelectrolyte gels
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Size distributions of metal nanoparticles in polyelectrolyte gels

机译：聚电解质凝胶中金属纳米粒子的尺寸分布

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Small-angle x-ray scattering is used to study size distributions of noble metal nanoparticles embedded in polyelectrolyte hydrogels with oppositely charged surfactants. A procedure is proposed to subtract matrix scattering and to extract pure scattering due to the nanoparticles allowing to evaluate their size distribution functions by means of a regularization technique. Two kinds of collapsed gel-surfactant complexes were studied: a complex of a cationic gel of poly(diallyldimethylammonium chloride) with an anionic surfactant sodium dodecyl sulfate (PDADMACl/SDS), and that of an anionic gel of poly(methacrylic acid) with a cationic surfactant cetylpyridinium chloride (PMA/CPC). Addition of a gold compound (HAuCl4. 3H(2)O) to the PDADMACl/SDS system forms the metal compound clusters and leads to a partial distortion of the gel structure. After subsequent reduction of the gold compound with sodium borohydride (NaBH4) ordering in the gel disappears and gold nanoparticles are formed. Their size distribution includes a fraction of small particles with approximately the same size as the compound clusters before reduction and a fraction of larger particles with the radii up to 40 nm. For the collapsed PDADMACl/SDS gels, aging does not change the size distribution profile; for the noncollapsed PDADMACl gels without surfactant, metal particles are found to grow with time. This suggests that the aggregation of metal colloids is prevented by the ordering in the collapsed gel-surfactant complex. The addition of HAuCl4. 3H(2)O and the subsequent reduction of the metal ions in the PMA/CPC system does not distort the gel structure as the degree of incorporation of AuCl4- ions is very low. Particle sizes in the PMA/CPC system are found to be somewhat larger than those in the PDADMACl/SDS system. The PDADMACl/SDS gels loaded with the PtCl4 compound were also studied to analyze the influence of the reducing agent type on the particle size distribution distributions. Fast reduction with NaBH4 yielded mostly small particles with the radii around 2 nm grown from the compound clusters similar to those observed for the gold-loaded gels. In contrast, slow reduction with N2H4. H2O was found to produce larger nanoparticles and the size distribution function shows a major fraction of the particles with the radii up to 30 nm. (C) 1998 American Institute of Physics. [S0021-9606(98)52048-X]. [References: 24]
机译：小角X射线散射用于研究嵌入带相反电荷表面活性剂的聚电解质水凝胶中的贵金属纳米粒子的尺寸分布。提出了一种减少基质散射并提取纯散射的方法，这归因于纳米颗粒，允许通过正则化技术评估其尺寸分布函数。研究了两种塌陷的凝胶表面活性剂配合物：聚（二烯丙基二甲基氯化铵）阳离子凝胶与阴离子表面活性剂十二烷基硫酸钠（PDADMACl / SDS）的配合物，以及聚（甲基丙烯酸）阴离子凝胶与表面活性剂的配合物。阳离子表面活性剂十六烷基吡啶鎓氯化物（PMA / CPC）。向PDADMACl / SDS系统中添加金化合物（HAuCl4.3H（2）O）会形成金属化合物簇，并导致凝胶结构的部分变形。随后用硼氢化钠（NaBH4）还原金化合物后，凝胶中的有序消失，形成金纳米颗粒。它们的尺寸分布包括一小部分小颗粒，其大小与还原前的化合物簇大致相同，以及一小部分半径最大为40 nm的大颗粒。对于塌陷的PDADMACl / SDS凝胶，老化不会改变其尺寸分布曲线。对于没有表面活性剂的未塌陷的PDADMACl凝胶，发现金属颗粒随时间增长。这表明通过塌陷的凝胶表面活性剂复合物中的有序化可以防止金属胶体的聚集。添加HAuCl4。 3H（2）O和随后的PMA / CPC系统中金属离子的还原不会使凝胶结构变形，因为AuCl4-离子的掺入程度非常低。发现PMA / CPC系统中的粒度比PDADMACl / SDS系统中的粒度大一些。还研究了负载PtCl4化合物的PDADMACl / SDS凝胶，以分析还原剂类型对粒度分布分布的影响。用NaBH4进行快速还原，产生的大多数小颗粒的半径与复合金簇中所观察到的相似，从化合物簇中生长出来的半径约为2 nm。相反，使用N2H4的还原速度较慢。发现H 2 O产生较大的纳米颗粒，并且尺寸分布函数显示出半径最大为30 nm的大部分颗粒。 （C）1998美国物理研究所。 [S0021-9606（98）52048-X]。 [参考：24]

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