This paper reports the synthesis and the physicochemical characterization of two series of gellan gum (GG) derivatives functionalized with alkyl chains with different number of carbon, from 8 to 18. In particular, low molecular weight gellan gum samples with 52.6 or 96.7 kDa, respectively, were functionalized with octylamine (C₈), dodecylamine (C₁₂) and octadecylamine (C₁₈) by using bis(4-nitrophenyl) carbonate (4-NPBC) as a coupling agent.

Thermo-rheological and ionotropic crosslinking properties of these gellan gum-alkyl derivatives were evaluated and related to the degree of derivatization in alkyl chains. Results suggested as length and degree of derivatization differently influenced coil-to-helix gelation mechanism of GG derivatives, ionotropic crosslinking, and strength of crosslinked hydrogels obtained in CaCl₂ 0.102 M and NaCl 0.15 M.

Statement of hypothesis The insertion of alkyl chains on the gellan gum backbone interferes with coil-to-helix transition mechanism and allows the production of hydrophobically assembled hydrogels.

本文报道了用不同碳数（从8到18）的烷基链官能化的两个系列吉兰糖胶（GG）衍生物的合成和理化特性。特别是分别具有52.6或96.7 kDa的低分子量吉兰糖胶样品通过使用碳酸双（4-硝基苯基）酯（4-NPBC）作为偶联剂，用辛基胺（C ₈），十二烷基胺（C ₁₂）和十八烷基胺（C ₁₈）将其官能化。

对这些结冷胶-烷基衍生物的热流变和离子交联性能进行了评估，并与烷基链的衍生化程度有关。结果表明，衍生化的长度和程度不同地影响了GG衍生物的盘绕-螺旋凝胶化机理，离子交联以及在CaCl ₂ 0.102 M和NaCl 0.15 M中获得的交联水凝胶的强度。

假设陈述结冷胶主链上烷基链的插入会干扰线圈到螺旋的转变机理，并允许生产疏水组装的水凝胶。