本文選題：聚電解質(zhì)　切入點：塌縮　出處：《高分子學報》2017年12期 　論文類型：期刊論文

【摘要】：采用并行回火蒙特卡羅方法,研究了聚電解質(zhì)單鏈在鹽溶液中的構象轉(zhuǎn)變以及離子的凝聚行為.對不同鹽濃度以及不同價態(tài)的情況,得到了鏈均方回轉(zhuǎn)半徑(Rg2)隨Bjerrum長度lB的變化曲線.模擬結果表明,在不同濃度與價態(tài)的鹽溶液中,隨著lB的增加,鏈先伸展,然后收縮,最終形成塌縮態(tài).鏈尺寸受鹽濃度與價態(tài)的影響,在中等lB范圍內(nèi),隨著單價鹽的加入,Rg2逐漸減小.而加入少量的高價鹽則會引起Rg2更加顯著得減小,這主要是由于高價反離子的凝聚造成的.對于高價鹽,在一定的lB范圍內(nèi),隨著鹽濃度的增加,存在Rg2先減小后增大的現(xiàn)象.在高價(如二價或三價)鹽溶液中,當高價反離子的總電量大于鏈電量時,高價反離子和共離子(與鏈帶同種電荷的離子)都發(fā)生凝聚,而單價反離子幾乎不發(fā)生凝聚;并且存在高價離子過度補償引起的鏈有效電荷反轉(zhuǎn).
[Abstract]:A parallel tempering Monte Carlo method was used to study the conformation transition of polyelectrolyte single chain in salt solution and the condensation behavior of ions. The curve of chain mean square radius of rotation (Rg2) with the length of Bjerrum is obtained. The simulation results show that in salt solutions with different concentrations and valence states, the chain expands first and then shrinks with the increase of LB. The chain size was affected by the concentration and valence of salt and gradually decreased with the addition of monovalent salt Rg2. However the addition of a small amount of high salt would result in a more significant decrease of Rg2. This is mainly caused by the condensation of high valence counter ions. In a certain range of lb, with the increase of salt concentration, Rg2 decreases first and then increases. In the solution of high valence salt (such as divalent or trivalent), When the total charge of the high valence counter ion is larger than the chain charge, both the high valence counter ion and the common ion (with the same charge as the chain charge) are condensed, while the univalent counter ion is almost not condensed. And there is the chain effective charge reversal caused by the overcompensation of high valence ions.
【作者單位】： 南開大學物理科學學院;
【基金】：國家自然科學基金(基金號21574071,21528401,20925414,91227121) 教育部創(chuàng)新團隊發(fā)展計劃(項目號IRT1257) 高等學校學科創(chuàng)新引智計劃(項目號B16027)資助
【分類號】：O631
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本文編號：1639660