<div><br></div><div><section class="_135editor" data-role="paragraph" style="font-size: medium; max-inline-size: 100%; margin: 0px; padding: 0px; border: 0px none; z-index: 0; overflow-wrap: break-word !important; outline: none 0px !important;"><p style="max-inline-size: 100%; margin-bottom: 0px; clear: both; min-height: 1em; cursor: text; line-height: 1.75em; overflow-wrap: break-word !important; outline: none 0px !important;"><span style="max-inline-size: 100%; margin: 0px; padding: 0px; cursor: text; font-size: 15px; overflow-wrap: break-word !important; outline: none 0px !important;">　　答表面活性剂分子是由亲水基和疏水基组成的，当表面活性剂溶解于水中时，亲水基与水分子有较大的吸引力，疏水基与水分子排斥而指向空气。这样表面活性剂分子有序排列在液体表面，在水和空气界面上形成定向吸附。吸附作用的结果，使原来水一空气界面逐步被疏水基一空气界面所代替，改变了水分子和空气分子直接接触的状况，从而降低了水的表面张力。如果表面活性剂的浓度增加到一定程度，则空气一水的界面聚集了更多的表面活性剂分子，并毫无间隙地密布于界面上，形成一层紧密的单分子膜，即界面吸附达到饱和状态，即水的表面张力已下降到最低程度。此时，如再提高表面活性剂浓度，此时表面活性剂分子为了稳定地存在于水中，能相互聚集在一起，排列成疏水基向里，亲水基向外的胶束。</span></p><p style="max-inline-size: 100%; margin-bottom: 0px; clear: both; min-height: 1em; cursor: text; overflow-wrap: break-word !important; outline: none 0px !important;"><br style="max-inline-size: 100%; margin: 0px; padding: 0px; overflow-wrap: break-word !important; outline: none 0px !important;"></p><p style="max-inline-size: 100%; margin-bottom: 0px; clear: both; min-height: 1em; cursor: text; line-height: 1.75em; overflow-wrap: break-word !important; outline: none 0px !important;"><span style="max-inline-size: 100%; margin: 0px; padding: 0px; cursor: text; font-size: 15px; overflow-wrap: break-word !important; outline: none 0px !important;">　　表面活性剂形成胶束的最低浓度叫临界胶束浓度(Critical micelle Concentration,简称CMC)。当表面活性剂浓度大于临界胶束浓度时，胶束数量随之增加，水的表面张力不再下降。</span></p><p style="max-inline-size: 100%; margin-bottom: 0px; clear: both; min-height: 1em; cursor: text; overflow-wrap: break-word !important; outline: none 0px !important;"><br style="max-inline-size: 100%; margin: 0px; padding: 0px; overflow-wrap: break-word !important; outline: none 0px !important;"></p><p style="max-inline-size: 100%; margin-bottom: 0px; clear: both; min-height: 1em; cursor: text; line-height: 1.75em; overflow-wrap: break-word !important; outline: none 0px !important;"><span style="max-inline-size: 100%; margin: 0px; padding: 0px; cursor: text; font-size: 15px; overflow-wrap: break-word !important; outline: none 0px !important;">　　临界胶柬浓度是一重要界限，在高于或低于临界胶束浓度时，其水溶液的表面张力以及其他许多物理性质都有很大的差异。不同表面活性剂具有不同的临界胶束浓度，这与许多因素有关。如疏水基愈长，疏水作用愈强，临界胶束浓度值愈小。亲水基数愈多，亲水性愈强，或亲水基位于疏水基中间，则临界胶束浓度值愈大。若加入电解质，表面活性剂易发生聚集作用，使临界胶束浓度值下降。</span></p><p style="max-inline-size: 100%; margin-bottom: 0px; clear: both; min-height: 1em; cursor: text; overflow-wrap: break-word !important; outline: none 0px !important;"><br style="max-inline-size: 100%; margin: 0px; padding: 0px; overflow-wrap: break-word !important; outline: none 0px !important;"></p><p style="max-inline-size: 100%; margin-bottom: 0px; clear: both; min-height: 1em; cursor: text; line-height: 1.75em; overflow-wrap: break-word !important; outline: none 0px !important;"><span style="max-inline-size: 100%; margin: 0px; padding: 0px; cursor: text; font-size: 15px; overflow-wrap: break-word !important; outline: none 0px !important;">　　表面活性剂的临界胶束浓度一般都不高，在0．001～0．02mol／L或0．02％～0.4％。在使用时一般应稍大于临界胶束浓度，才能充分发挥其作用。润湿和渗透作用只需在界面吸附，表面活性剂分子(或离子)溶液浓度稍高于CIVIC即可显示其效果；而乳化、分散、增溶、净洗作用需要大量胶束，因此溶液浓度必须超过CIVIC较多，始能有所作用。</span></p><p style="max-inline-size: 100%; margin-bottom: 0px; clear: both; min-height: 1em; cursor: text; overflow-wrap: break-word !important; outline: none 0px !important;"><br style="max-inline-size: 100%; margin: 0px; padding: 0px; overflow-wrap: break-word !important; outline: none 0px !important;"></p></section><section class="_135editor" data-role="paragraph" id="autoparagraph" style="font-size: medium; max-inline-size: 100%; margin: 0px; padding: 0px; border: 0px none; z-index: 0; overflow-wrap: break-word !important; outline: none 0px !important;"><p style="max-inline-size: 100%; margin-bottom: 0px; clear: both; min-height: 1em; cursor: text; overflow-wrap: break-word !important; outline: none 0px !important;"><br style="max-inline-size: 100%; margin: 0px; padding: 0px; font-family: 微软雅黑, &quot;Microsoft YaHei&quot;, sans-serif; font-size: 17px; caret-color: rgb(255, 0, 0); overflow-wrap: break-word !important; outline: none 0px !important;"></p></section></div>