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In this study, we demonstrate that doping the ferroelectric nematic material RM734 with cationic polymers enables the formation of polymeric micelles that connect pairs of half-integer topological defects. Polarizing optical microscopy reveals that these string defects exhibit butterfly textures, featured with a 2D polarization field divided by N\u00e9el-type kink walls into domains exhibiting either uniform polarization or negative splay and bend deformations. Through analysis of electrophoretic motion and direct measurements of polarization divergences, we show that the string micelles are positively charged, and their side regions exhibit positive bound charges. To elucidate these observations, we propose a charge double-layer model for the string defects: the positively charged cationic polymer chains and densely packed RM734 molecules form a Stern charge layer, while small anionic ions and positive bound charges constitute the charge diffusion layer. Notably, our experiments indicate that only cationic polymer doping effectively induces the formation of these unique string defects. These findings enhance our understanding of ionic doping effects and provide valuable insights for engineering polar topologies in liquid crystal systems.<\/jats:p>","DOI":"10.1093\/pnasnexus\/pgae552","type":"journal-article","created":{"date-parts":[[2024,12,10]],"date-time":"2024-12-10T23:06:35Z","timestamp":1733871995000},"source":"Crossref","is-referenced-by-count":5,"title":["Half-integer topological defects paired via string micelles in polar liquids"],"prefix":"10.1093","volume":"3","author":[{"given":"Zhongjie","family":"Ma","sequence":"first","affiliation":[{"name":"Department of Mechanical and Energy Engineering, Southern University of Science and Technology , Shenzhen 518055 ,","place":["China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0006-0544-5633","authenticated-orcid":false,"given":"Miao","family":"Jiang","sequence":"additional","affiliation":[{"name":"Department of Mechanical and Energy Engineering, Southern University 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