Gelation phase diagrams of colloidal rod systems measured over a large composition space

He, Shiqin; Caggioni, Marco; Lindberg, Seth; Schultz, Kelly M.

doi:10.1039/d2ra00609j

Cited by 2 publications

(2 citation statements)

References 51 publications

(131 reference statements)

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“…Bulk rheology is also used to characterize the gelation of OMFC in anionic or cationic surfactant solutions. Bulk rheology measures gelation on a longer time scale and also measures larger values of moduli not accessible with microrheology . In bulk rheology, we first immerse 1.27 wt % OMFC in 5 wt % SDS or BDDAB to induce gelation and perform a 4000 min time sweep measurement (Figure a).…”

Section: Results and Discussionmentioning

confidence: 99%

“…Bulk rheology measures gelation on a longer time scale and also measures larger values of moduli not accessible with microrheology. 68 In bulk rheology, we first immerse 1.27 wt % OMFC in 5 wt % SDS or BDDAB to induce gelation and perform a 4000 min time sweep measurement ( Figure 8 a). With bulk rheology, different trends in rheological properties for OMFC gelled in different surfactants are measured.…”

Section: Results and Discussionmentioning

confidence: 99%

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Characterizing Phase Transitions of Microfibrillated Cellulose Induced by Anionic and Cationic Surfactants

He,

Afshang,

Caggioni

et al. 2023

Langmuir

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Rheological modifiers are used to tune rheology or induce phase transitions of products. Microfibrillated cellulose (MFC), a renewable material, has the potential to be used for rheological modification. However, the lack of studies on the evolution in rheological properties and structure during its phase transitions has prevented MFC from being added to consumer, fabric, and home care products. In this work, we characterize surface-oxidized MFC (OMFC), a negatively charged colloidal rod suspension. We measure the rheological properties and structure of OMFC during sol−gel phase transitions induced by either anionic or cationic surfactant using multiple particle tracking microrheology (MPT). MPT tracks the Brownian motion of fluorescent probe particles embedded in a sample, which is related to the sample's rheological properties. Using MPT, we measure that OMFC gelation evolution is dependent on the charge of the surfactant that induces the phase transition. OMFC gelation is gradual in anionic surfactant. In cationic surfactant, gelation is rapid followed by length scale-dependent colloidal fiber rearrangement. Initial OMFC concentration is directly related to how tightly associated the network is at the phase transition, with an increase in concentration resulting in a more tightly associated network with smaller pores. Bulk rheology measures that OMFC forms a stiffer structure but yields at lower strains in cationic surfactant than in anionic surfactant. This study characterizes the role of surfactant in inducing phase transitions, which can be used as a guide for designing future products.

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Section: Results and Discussionmentioning

confidence: 99%

Section: Results and Discussionmentioning

confidence: 99%