SANS quantification of bound water in water-soluble polymers across multiple concentration regimes

Abstract

Small-angle neutron scattering is used to measure the number of bound water molecules associating with three polymers over a wide concentration range. Different fitting workflows are evaluated and recommended depending on the concentration regime.

Conformation of Network Strands in Polymer Gels

“…The Debye equation assumes θ conditions and a single chain signal, which is supported based on the Correlation Length Scaling and Contrast Matching Analysis detailed in the SI (Figures S3 and S4). An error estimate calculated with the bootstrapping method resulted in similar uncertainties, as reported from the confidence interval of the fit (Figure S5). An alternative method used to extract the radius of gyration is the Guinier approximation: ln ( I ) ∼ prefix− q 2 R normalg 2 3 nobreak0em1em⁢ normalwhere nobreak0em1em⁢ q R normalg < 1 Guinier plots of ln( I ) versus q 2 can thus be used to determine the radius of gyration without any assumptions related to the model or solvent quality; plots for the contrast matched gels are shown in Figure b, with corresponding R g values and prestrain values reported in Table .…”

A coordination strategy to achieve instant dissolution of a biomedical polymer in water via manual shaking

“…Moreover, while most studies are related to the dissolution of polymers in organic solvents, dissolution of a polymer especially a biomedical polymer in water has rarely been investigated, although water is an important solvent and can interact with some polymers. 7…”

“…Moreover, while most studies are related to the dissolution of polymers in organic solvents, dissolution of a polymer especially a biomedical polymer in water has rarely been investigated, although water is an important solvent and can interact with some polymers. 7 The so far reported approaches to accelerate polymer dissolution are mainly based on the promotion of swelling and chain unwinding. [8][9][10][11] In practice, stirring, solvent exchange, temperature control, and addition of a solubilizer are often used to accelerate polymer dissolution.…”

Intrinsic-water desorption induced thermomechanical response of hydrogels

“…The coexistence of three different types of water in hydrogels, i.e., tightly bound water, loosely bound water, and free water, is already reported. [12][13][14][15][16][17][18][19][20] The different kinds of water are classified based on their freezing characteristics. The different types of water that exist in a hydrogel network can be explained as follows: tightly bound water (type-III) binds strongly to the hydrophilic functional group of the polymer and its freezing temperature is undetected over a wide temperature range from À70 1C to 0 1C; 21 loosely bound water (type-II) has a freezing temperature less than that of the bulk water and is generally clustered around the strongly bound water and interacts with the functional group by weak hydrogen bonds; and lastly, the free/bulk water (type-I) has a freezing temperature similar to that of bulk water, does not interact with the polymer, and is present in the free volume or voids in the polymer matrix.…”