Hydrophobic
self-assembly pairs diverse chemical precursors and
simple formulation processes to access a vast array of functional
colloids. Exploration of this design space, however, is stymied by
lack of broadly general, high-throughput colloid characterization
tools. Here, we show that a narrow structural subset of fluorescent,
zwitterionic molecular rotors, dialkylaminostilbazolium sulfonates
[DASS] with intermediate-length alkyl tails, fills this major analytical
void by quantitatively sensing hydrophobic interfaces in microplate
format. DASS dyes supersede existing interfacial probes by avoiding
off-target fluorogenic interactions and dye aggregation while preserving
hydrophobic partitioning strength. To illustrate the generality of
this approach, we demonstrate (i) a microplate-based technique for
measuring mass concentration of small (20–200 nm), dilute (submicrogram
sensitivity) drug delivery nanoparticles; (ii) elimination of particle
size, surfactant chemistry, and throughput constraints on quantifying
the complex surfactant/metal oxide adsorption isotherms critical for
environmental remediation and enhanced oil recovery; and (iii) more
reliable self-assembly onset quantitation for chemically and structurally
distinct amphiphiles. These methods could streamline the development
of nanotechnologies for a broad range of applications
